HMS Hero is undergoing a self-maintenance period in Gibraltar after several months without a captain or first lieutenant. After the arrival of Lieutenant Commander Beaumont and Commander Nialls, a random incident with a crew member in a bar leads to a civilian ship suspected of gun running. When the ship leaves port with its cargo, HMS Hero takes pursuit and forces the ship to stop in international waters, where the doctrine of hot pursuit is explained to its crew.

Hero arriving at Malta is reassigned at short notice to pick up a defecting Russian diplomat from the North African coast. The risking of a frigate and its crew of over 200 causes questioning of the "request" down the line of command, with each man aware that his superior will abandon him if anything goes wrong. Although the foreign coast guard detects and responds to the intrusion with a surveillance helicopter and MTB, Hero collects the Russian and escapes without injury, although it turns out that he may be of little value. In the repercussions, a government official says "it was expected to be a simple submarine operation, nobody said frigate".

Hero is assigned at short notice to take part in a naval exercise. Stores accountant Rabbits who had been planning to visit his pregnant wife but now can not leave the ship, receives a letter in which she says she is depressed and thinking of getting rid of the baby. Meanwhile, Marine Engineering Mechanic (stoker) Cutler and his chief Slater come into conflict, climaxing when Cutler lashes out and kicks Slater in the head. Rabbits sabotages a bearing in the ship's propulsion system with an oil dispersing agent, forcing Hero to withdraw to Gibraltar on one engine. At Cutler's on-board trial, he is accused of both assault and sabotage. However, evidence implicating Rabbits is found. Cutler is cleared of both charges and Rabbits is convicted instead.

Petty Officer Willows leaves the ship to sort out the debts run up by his oniomaniac wife. While at home, he is approached by a foreign agent who impersonates naval security, obtaining a confession for smuggling and then blackmailing him into becoming a spy. Back on the ship, he photographs documentation for a new submarine detection system. However, when Nialls finds out about his debts, he has him transferred off the ship and calls in the real naval security for further investigation.

With Hero at Malta, Chief petty officer Donovan, who previously had criminal dealings with a man named Spiro, goes ashore to recover his money which he had left in the hands of his girlfriend Gina. However Gina is now living with Spiro and between them they have disposed of it. Gina's death is faked and Donovan is threatened with being framed for the "murder" if he doesn't deliver an advanced electronic valve from Hero. He is caught with the valve while leaving the ship, but the British intelligence services want the delivery to go ahead in an attempt to capture a Soviet scientist. The scientist turns out to be a woman who has been socialising with the officers of Hero, but she evades capture.

Hero encounters an abandoned freighter at sea off the regular shipping lanes. A boarding party searches the ship and discovers explosive charges set to go off, but as they leave the ship, AB Drew falls off a ladder below decks and suffers a potential back injury, making him difficult to move. Beaumont and Master-at-arms Heron defuse a plastic explosive, a limpet mine and a depth charge, the latter with the help of the appointed explosives expert Lieutenant Parry, who turns out to be terrified of the job. Hero takes the freighter in tow, which will allow the crew to share the salvage prize and thwart the presumed insurance fraud.

Hero takes part in an exercise with the submarine HMS Omega. ABs Wallace and Pomeroy from Hero go aboard Omega as visitors. Omega attempts to hide from Hero by bottoming on the sea floor at 160 feet. However, it strikes a WW2 mine and its accommodation compartment is holed. Once the compartment is sealed off, Wallace and Pomeroy are trapped in the forward torpedo bay. With the sub unable to surface and the aft escape tower out of service, the only option for survival is for divers from Hero to repair the hole. Pomeroy panics and attempts to flood the torpedo bay and use the forward escape tower, an action that would doom the submarine's crew, but is physically restrained by Wallace. Once the hole has been patched, the submarine safely surfaces.

Hero arrives at Hafsidia, the capital of the Arabic-speaking state of Hafsidia. Its government has heard rumours that Britain is considering selling a frigate to Israel, and demands that Britain promise never to do such a thing, with a threat to seize Hero if a deadline is not met. When Nialls hears that Britain will reject the demand, he must arrange an escape, with the assistance of a British agent named Tashing. Replacement engine oil is floated across the harbour at night, 22 of Hero's sailors are rescued from detention onshore, and Hero evades guards on the wharf, artillery pieces, a mined boom across the harbour, a gunboat, and two approaching (presumably Russian) frigates. Lieutenant Parry is killed by a rifle shot from shore, but Hero heads for a liaison with her sister ship HMS Phoebe.

With Hero at Gibraltar, Master-at-Arms Frank Heron applies for extended service, but is shocked when it is rejected. He argues with his girlfriend Maura who is returning to England. Also in port is HMS Boadicea, commanded by Commander Murton, who Heron blames for putting a black mark on his record. At an on-shore party, Murton argues with his own girlfriend, Peggy Carter, who he wants to break up with. A drunk Heron arrives to confront Murton, but he is taken back to the ship. Murton and Nialls, drunk, make a bet of £500 over which ship can get back to England first. Nialls tells Heron to pull himself together. Murton sabotages Niall's chances by having him delayed at the base, but Nialls phones Peggy Carter, who arranges for her connections to send Boadicea on a bogus assignment, allowing Nialls to win the bet. Back in England, Heron is apparently marrying Maura.

Hero is under battle conditions, after a hostile force has invaded northern Norway. On board is a squad of Royal Marine Commandos led by Lieutenant Palfrey, whose father was a highly decorated WWII general. Deployed from Hero to blow up an enemy radar station ashore, the squad is captured and Palfrey taken for questioning. He explodes when compared unfavourably to his famous father, breaks his interrogator's neck, and escapes into the countryside. The final minutes of the episode reveal that the entire scenario was a NATO training exercise, and Palfrey has killed a Norwegian Army officer - and now the Army, the police, and Commander Nialls have to find him.

Lieutenant Palfrey escapes his pursuers and returns to Hero where he speaks with Nialls. Nialls persuades the Norwegians to allow him to be court-martialled in England. He pleads not guilty but is convicted of manslaughter, but after Nialls speaks as a character witness he is sentenced to only 18 months imprisonment and discharge from the service, but giving the Admiralty Board the option to remit the discharge and suspend the imprisonment.

An Arab guerrilla unit hijacks a British fleet auxiliary armament stores ship in the North Atlantic, which is carrying Polaris nuclear warheads. Hero as the closest warship is sent to intervene. The hijackers refuse to stop the ship, threatening to kill the crew. When they refuse to negotiate, and even refuse orders from their own political leaders to surrender, Nialls is ordered to sink the ship. However, he first fires a few mortar bombs near the bow, and the hijackers finally agree to surrender.

Hero takes on a new deputy weapons and electrical officer, Sub Lieutenant Penn, who has recently graduated with a Navy-sponsored university science degree and has a five year work obligation. However, he has decided while at university as an anti-authoritarian that the military is obsolete and he wants to be a modern leader in business. He comes into conflict with Beaumont, who is a strong believer in all naval traditions. Nialls wants to make an effort to keep Penn in the service, since he represents a new generation of graduates with badly-needed modern skills such as electronics. However, the dispute between Penn and Beaumont is brought to a head at a commemoration of the Battle of Trafalgar, held at sea at the place of battle. Nialls and Beaumont argue, and Nialls reluctantly grants Penn's desire to be recommended for release from service.

After 3 weeks in port and with a restless crew, Hero is delayed from departure for several hours, leading to events that would otherwise have been avoided. Leading regulator Fuller plays a cat-and-mouse game with Constable Munk, husband of the woman with whom he spent the night. A party of Sea Cadets runs wild on the ship. The head of the frigate squadron, Captain Calder (F), visits for lunch, along with the daughter of a stripper from a nightclub. Preventing unwanted encounters between the guests taxes Last and Beaumont.

Hero picks up survivors from a crashed Boeing 707 near St Kilda, Scotland. A doctor is landed on the ship and operates on one of the survivors, who must be taken to Stornoway as quickly as possible. However, another survivor is Lander alias Maritain, a Venezuelan revolutionary who suspects that the plane was bombed by the CIA. Two officials from the FCO are landed on the ship, but one turns out to be American. Nialls initially refuses an order from the MOD to stop the ship and allow Lander to be secretly removed, using the excuse that the patient must be dispatched to hospital. However, when the patient dies, he tests Lander and finds him unworthy of further protection.

When Beaumont is bringing Hero into Portsmouth, Nialls takes control at a critical moment, which for Beaumont continues a pattern where he isn't trusted by Nialls. He seriously considers taking a job he is offered to run a yacht chartering company, also in the hope that it would improve his chances with an ex-girlfriend. Meanwhile, Nialls visits his own girlfriend in Exeter, but she is unhappy with the part-time relationship. Back on the ship, Hero must complete a challenging replenishment at sea maneuver. Nialls, although suffering from gastric flu insists on doing it himself, but makes a mess of it and reluctantly hands control to Beaumont. Completing the operation perfectly, his confidence is restored and he tells Nialls that he will refuse the job offer. The two men hope for the best with their respective relationships.

The crew of a British trawler, fed up with their skipper's erratic performance, confine him to his cabin and take over the boat. A loyal crew member sends a distress signal, and Hero on fishery protection duty investigates. The crew claim that they confined him for his own protection after he become drunk and violent. The skipper initially refuses to leave his cabin to meet a boarding party, using a handgun as a deterrent, but is eventually taken to Hero. A doctor diagnoses carcinoma of the stomach, giving him no more than three months to live, but he was already aware of the disease and was hoping to die at sea. After Nialls convinces him not to press charges for mutiny, he resumes command of the trawler.

Hero takes on two new sailors at Plymouth, O.S. Jones and L.S. Steele, and departs for an exercise in the Arctic. Steele quickly comes into conflict with AB Radcliffe, who had been a Petty Officer above Steele on a previous ship but has since been demoted. When Steele presses charges against Radcliff for refusing an order, Radcliffe threatens Steele. At night, Steele is alone writing a letter and goes on deck to fix a noisy tarp on a boat, but falls overboard. Nobody notices that he is missing until the next day, when Hero reverses course to search. Radcliff is under suspicion, although he notices the loose tarp and points it out to Nialls. After a day and night searching, with little hope that Steele would still be alive in the cold water, he is nevertheless rescued.

Hero is instructed to pick up a German government minister, Lescher, who wishes to observe an exercise involving Hero and a German submarine. Nialls is mystified by the request, but when he discovers that Lescher is ex-navy, unwell, suffering nightmares and possibly suicidal, he requests Lescher's military service records from the MOD. These reveal that Lescher was a top U-boat captain, the sole survivor of his submarine when it was fired on by a British ship when trying to surrender. When the exercise takes place, Hero detects the submarine and fires mortars, and the submarine surfaces, during which time Lescher has become more and more panicked. He is taken to a cabin, and reveals to Nialls that the exercise was a close reenactment of his final submarine battle, and he was hoping it would help with his nightmares and flashbacks.

Hero receives a new commander Alan Glenn, a Phantom pilot, upsetting Beaumont who once again thinks that his navy career has stalled. They are called to an emergency: a Russian submarine is immobilized near Jan Mayen, an island in the Arctic Ocean, and Captain Herrick joins the ship. An expert on submarines, he is keen to obverve the Russian vessel, but he also has a history with Glenn, who he blames for the death of his brother in a Phantom accident. Herrick pushes Glenn to take Hero through a dangerous moving ice field to try reach the sub before a pair of Russian destroyers. Beaumont points out to Glenn that Herrick is also suffering as a relative underperformer in an illustrious naval family, with his brother the Second Sea Lord, and is looking for a chance for promotion. However, Hero must retreat in the face of terrible sea conditions, barely escaping the ice with only minor damage.

Hero boards and searches the Appleton Lady, a boat suspected of drug smuggling, but nothing suspicious is found. However, Glenn observed them dumping items overboard and asks to speak to the captain, who is an old friend named Kenyon. Kenyon gives his word that they were not smuggling drugs, but only items such at watches. Glenn says he owes him a favour, and allows him to leave without reporting the dumped items. Some time later, Hero is asked again to find the boat, after it was seen picking up drugs near Scheveningen. Hero finds it once again, and this time uses the Wasp to net a discarded item before it sinks. Glenn again interviews Kenyon, and shows him the recovered heroin. Kenyon claims he needed the money for treatment for his sick child, but Glenn in disbelief has him detained. In court, Kenyon pleads guilty and doesn't mention the child, but Glenn visits Kenyon's wife and finds that the story was true and the child is dead, and that he hadn't mentioned it in court to keep the information from the child. Later, Glenn reveals to a friend that Kenyon had saved his navy career, by taking the blame for a prank gone wrong which both had organized.

Guest cast: Matthew Long as David Kenyon, Marian Diamond as Sue Herrick, Claire Nielson as Valerie Kenyon, Roy Boyd as Joe Murphy, John Barcroft

Hero finds a stationary yacht, the Knight Errant, west of the Azores. The lone yachtsman is acting erratically, using a chart from 1938 and having smashed his radio with an axe, and he refuses to give his name or accept any offer of assistance. Glenn is uncertain whether to intervene, and dislikes lone yachtsmen in general, but they are defended by Beaumont who is planning a solo voyage of his own. Glenn insists on the yachtsman joining him on Hero for lunch, and is informed by the MOD that he is a renowned sailor and former British Vice Admiral whose wife recently died. The yachtsman returns to his boat, but after some research, Glenn concludes that he is planning to kill himself at a location from his voyage of 1938, which he had described in a book. Glenn talks with the yachtsman on his boat, who reveals that he considers his whole life to be a fraud, and now that his wife is gone he is planning to disappear quietly without damaging the legend that had inspired so many. Glenn allows him to sail off.

Hero is undergoing maintenance, with Peek temporarily replacing Beaumont as second in command, and Glenn staying at the home of the port admiral Brinton. Peek's disdainful attitude towards dockworkers causes the foreman to warn him that there has been simmering industrial trouble and he should take care. Meanwhile, Glenn spends time with Brinton's wife Julia, with whom he had an affair ten years ago while Brinton was away. Julia is bored and interested in restarting the affair, which Glenn declines. Peek infuriates the dockworkers when he orders Fuller to tidy up some work in progress, and Hero is put on a blacklist preventing further work. Glenn is called back, but not before Brinton notices his intimacy with Julia, who admits to the previous affair. Glenn, back on the ship and ultimately responsible, needs Brinton's help to resolve the dispute, but is anxious that Brinton will instead destroy his career, while Peek is also expecting the worst. Ultimately, Brinton helps by sending Hero on a bogus urgent sailing to "save lives", allowing the dockworkers to resume work without losing face. Glenn tells Brinton that he won't take action against Peek, since promising careers should not be destroyed just because of one youthful mistake.

Hero performs poorly in exercises with the submarine HMS Ovid. Beaumont blames Glenn, saying that the team always performed well under Nialls. Glenn invites the commander of Ovid to his cabin, who turns out to be a friend named Tremayne. They reminisce over naval school days, and Glenn is reminded that he gave "Porky" Beaumont his nickname, as a pun on "bore". Meanwhile, the rest of the officers hold a meeting to plan the next day's activities, leaving Peek annoyed with Beaumont for keeping him back from his latest girlfriend. Tremayne advises Glenn that Beaumont is right, and Glenn is a terrible anti-submarine captain, and he needs to learn to listen to his crew, particularly Beaumont who is an expert. Tremayne agrees to hold an extra day of exercises with Hero to help Glenn figure it out, although this annoys Beaumont and Peek whose planning for the next day was now discarded. During the exercise, Glenn has some success, with Tremayne giving him an easy start, and then invites Beaumont to show what he can do. Ovid tries to escape but makes a navigation error and heads for a dangerous bank. Beaumont realises what has happened and manages to prevent an accident. Tremayne is grateful, and Glenn gives the credit to Beaumont and Peek.

Hero loses a popular crew member to acute peritonitis before he can be brought to shore, with the Wasp pilot Roy Tagg declining fly in weather conditions outside the operating envelope. Many of the crew and officers think he should have risked it. Meanwhile, the brother-in-law of the dead man, Graham Firth, is working at the Admiralty Experiment Works on stabilization of Leander-class frigates, and has a maverick theory of using the rudders to do the job of the stabilizers. He believes that this could have prevented his brother's death, by providing a stable platform for Wasp operations. After unauthorized tests on a model in a wave tank are successful, he convinces the head of research to perform a sea trial, and takes a team on board Hero. There is concern that the rudders weren't designed for stabilization and could be damaged. It is revealed that in a previous posting Tagg had been court-martialled for an accident when the Wasp was used outside its operating envelope. Firth asks for filming of the trials from the Wasp, but during the first run, Tagg reports strange vibrations and makes an emergency landing. The maintenance crew can not find any fault, putting Tagg under further pressure. After tension between Firth and Tagg, Tagg invites Firth to be the cameraman for the next run. The problem with the Wasp reoccurs, and this time causes restriction on cyclic control movement. He makes a difficult emergency landing, with Hero operating on rudder stabilization, giving vindication to both Tagg and Firth.

Hero receives a young new sailor Dorrity, who is assigned to a mess deck with the unruly Grogan, along with L/Reg Fuller who is supposed to keep things under control. Taking part in a tedious ten day patrol in the Atlantic, Glenn encourages the organization of sports and games to keep up morale. Fuller teaches Dorrity the game of Uckers, but Dorrity is pranked into thinking that he needs special permission to smoke a pipe and makes an unnecessary application to Heron. In another prank, a call is made in the daily orders for a volunteer to be the splash target coxswain, this being a raft towed behind the ship for aircraft to bomb. To the amazement of all, Dorrity applies for the job, and is given lessons in the mess on riding the device. Dorrity briefly steers the ship, which is so unsteady that Glenn sends a reprimand. An event is held in the mess to present to Dorrity a cake with a figurine of a splash target rider, but Dorrity is nowhere to be found. The ship is searched, and the Wasp scrambled, but ultimately Glenn spots him up the mast. He tells Dorrity that he needs to return to the mess deck, which he reluctantly does, where he is invited by Grogan to take his place in a game of Uckers.

When a crew member named Brewer is found dead on the minesweeper HMS Ferrington, a board of inquiry is held on Hero. Meanwhile, a detective is making enquiries about a missing teenage girl, Rita Kersey, who was friendly with Brewer. At the inquiry hearing, it appears that the death was a simple accident, where Brewer had been unsteady, perhaps drunk, and had fallen down a ladderwell, as witnessed by crew members Ellis and Lusher. Brewer had been out drinking in Folkestone with a friend Scobie. However, the next day, Kersey's body washes up on the beach, apparently murdered by suffocation, and her shoes are found on the Ferrington. Scobie eventually admits that Brewer had met her in Folkestone and offered her a trip home, hiding her on board, but had accidentally killed her while trying to keep her quiet. He asked Scobie to help throw the body overboard, but Scobie backed out, and after a struggle Brewer fell down the ladderwell. Ellis and Lusher had disposed of Kersey's body to avoid any trouble for the ship and its captain. The crew members are taken by the civil authorities, and Glenn informs the commander of Ferrington that he has been relieved of command, pointing out that he was responsible for everything that happened on the ship.

Hero is preparing for an inspection, to be conducted by Admiral Staunton and staff officer operations Mark Nialls. Glenn and Nialls became enemies years ago when Glenn dissuaded a woman from marrying Nialls, and Glenn is expecting a difficult "evolutions", where the crew is tested with unconventional problems. While Hero's officers are trying to obtain information, Nialls drops false hints; that the Admiral drinks only "planters rocket", which he discovered in Bermuda; and that he desperately wants the autograph of Lily Bevis, an aging actress. MAA Harry Burnett, who has replaced Heron, is dispatched with Fuller to obtain the autograph. Meanwhile, Peek and Kiley attempt in vain to find the recipe for planters rocket. Attending a naval reception, Peek obtains a glass of the drink from the barman, who refuses to divulge the recipe. Kiley subsequently gives it to the captain of HMS Zephyr to keep him away from Diana, a girl Glenn is interested in: the captain collapses after drinking it. Glenn is misinformed about Diana by Nialls, and offers her dinner and drives her home, which turns out to be at Northwood, 80 miles away. After suffering mishaps he doesn't return to Hero for several hours, by which time Peek is unconscious after trying to recreate planters rocket. Burnett and Fuller also arrive back late, after Burnett has spent many hours playing games such as Battleships and Snakes and Ladders with Bevis, but having obtained the autograph. However, the next day, a ship is needed to respond to an emergency, and since Zephyr is out of action due to the incapacity of her captain, Hero is sent, cancelling the inspection.

Glenn's brother Edward (Eddy), a Buccaneer pilot in the Fleet Air Arm is facing a court-martial after he apparently ignored a direct order and made a low pass over a ship, narrowly avoiding a collision. He asks Glenn to represent him, but refuses to explain why he did it. In court, he pleads not guilty to the charges of dangerous flying and disobeying an order, but his case goes badly after his observer Frank Caban takes the stand and says that the order had been received clearly. During a recess, Glenn asks Eddy about a young woman who was observing in court, and he says it is Anneke, Frank's new wife, but he becomes agitated and seems to be in physical pain. Glenn talks with a doctor who says that it could have been caused by emotional stress from the court, but he wouldn't have suffered stress during routine flying. However, Glenn concludes correctly that Eddy was in love with Anneke, and that the emotional stress of flying with Frank caused him to faint during the flight. He admits to this in court, and is subsequently acquitted but directed to the medical board to resolve the stress issues.

The Royal Navy is searching for millionaire Andrew Denecot's yacht, which was last seen leaving Gibraltar with Denecot and his family. A possible sighting is reported by an RAF Nimrod near the Canary Islands, and Hero is sent to investigate. Beaumont remembers its captain, Tony Loader, as a "colourful character". On the yacht, Loader has hijacked the yacht with a crew of criminals and a young woman. Hero sails close to the yacht, confirming its identify, although it has a false name and flag, and is ordered to board it. However, Loader tells Glenn to withdraw, or the Denecot family will be killed. Glenn asks for proof that they are still alive, and is permitted to visit the yacht using the Wasp, and confirms that the woman is Denecot's daughter. Glenn returns to Hero and agrees to withdraw to 20 miles distance. Loader plans to abandon the yacht using small boats to reach the African coast. However, Hero is ordered to board it by force. Glenn deploys two Geminis, commanded by Beaumont and Peek, which drop a rope in front of the yacht to foul its screws, forcing it to stop. They then board it, capturing the crew without casualties. The full story is then revealed: the Denecots were in financial trouble, and intended fake their deaths in a yacht sinking, while absconding with a box of cash. However, Loader decided to take the cash for himself, and the daughter, in love with Loader, had joined the plan, not realising that her parents would be killed.

Fuller's wife Norma unexpectedly arrives in Portsmouth from Glasgow, threatening a divorce unless he leaves the navy. Meanwhile on Hero, Lt Monty Wakelin wants Chief (CPO) Cook Mantell reverted to petty officer, on account of poor work and excessive drinking. Beaumont agrees, but Glenn wants them to spend more time trying to improve him. When Norma insists that Fuller stay with her in a hotel instead of returning to Hero, Glenn goes ashore to try to convince her to find a compromise. She agrees to let Fuller return to Hero, as long as he is back by 4:30. Mantell, drinking heavily in anticipation of his forthcoming meeting with Glenn and presumed demotion, goes to a galley and starts a fryer, then passes out. A fire breaks out, and Fuller, leaving to meet Norma, hears the alarm and sees smoke. He returns and helps Peek drag Mantell out of the galley; they ask Mantell if anybody else is inside, and he responds "petty officer". Fuller goes back in to search, but Mantell is just talking about his new rank. Fuller is caught in an explosion. Glenn phones Norma at the hotel, but she has already left for home.

Hero brings supplies to a scientific station at the usually uninhabited island of North Krona in the Outer Hebrides (North Krona is an apparently fictional island located near Barra Head, named similarly to North Rona.) The station is officially meteorological, but Glenn informs his officers that it is actually monitoring Soviet nuclear submarines. When Glenn and Peek lead two boats ashore, they are given an unexpectedly frosty reception by the head of the station, Anvey, who wants the supplies left on the beach and for Hero to depart as soon as possible. Glenn knows one of the two women on the station, Katharina, but she avoids contact with him, as do the other man and woman. The 5th member of the station, Lovett, is not present. Glenn directs some low-key investigations, and discovers that Anvey doesn't appear to have the right age or description, and that the station staff appear to be covering up for the missing man. Katharina visits Hero and talks with Glenn about their former relationship, which Glenn had ended but is willing to resume, but she doesn't say what's happening at the station. Glenn notices something odd about Anvey's qualifications, and returns to the station with an armed party. They detain the station members and enter the research hut, where as Glenn had inferred, they are not monitoring submarines for the MOD, but conducting dangerous biological weapons research for an intelligence service. Anvey admits that he is actually Lovett, and Anvey had died a few weeks ago in an accident. Instead of reporting it and having the station shut down, they had stored the body in a freezer to continue research which was close to a major breakthrough. Katharina and Glenn speak again, but it appears that neither is willing to put a relationship ahead of their career. Glenn leaves the station staff on the island pending his report.

Hero is in Hong Kong and takes on a new first lieutenant, James Napier. Meanwhile, Zoe Carter, a freelance journalist, arrives at the ship and meets the captain Edward Holt, a former submarine commander who has replaced Glenn. She goes on board to interview Thomas Meryon, a British member of parliament, and an opponent of the military, who is staying on Hero to observe its activities first-hand. They discuss Christopher Panmuir, who is at Hong Kong with his sailboat Windsong, and intends to sail to the site of a forthcoming French atmosperic nuclear test as a protest. Carter brings Panmuir to meet Meryon, and Meryon is persuaded to hold a press conference on board Hero to denounce the test. Carter and Holt go out to dinner and discuss Meryon and Holt's ex-wife. At the press conference, Meryon denounces the test, and Carter asks if he will sail in Windsong: put on a spot, he agrees as long as Carter comes along to report it. Holt tries to stop her going, without success. Panmuir, Meryon and Carter sail on Windsong, and Hero follows to keep an eye on things. They reach the test area, but are ignored by the French. They sail into the restricted area, demanding that the test be cancelled. Holt activates anti-nuclear measures on Hero and waits outside the zone. Once the test takes place, Windsong requests rescue, and Hero responds, sailing through fallout. Carter is collected, but Panmuir and Meryon decide to sail further. Panmuir hopes to make a larger statement with his death, while Meryon is tired of being considered a phoney.

At HMS Tamar in Hong Kong, Holt is introduced to Francis Corbin of the Foreign Office. Holt is told that an aircraft en route to Singapore has ditched near Vietnam, and Hero must sail urgently to recover a briefcase of extremely delicate papers. Holt protests that it would be very hard to find the wreck, and they should be looking for survivors, but he is instructed to find the papers and take them to the High Commissioner in Singapore. On Hero, Fuller is writing to his wife, who has just given birth to their first child. Hero sails to the reported crash location, and to their amazement the wreck is found immediately. Hans Anderson and Napier dive to the aircraft, easily recovering the briefcase, but find no bodies aboard. However, when a Russian "Bear" aircraft flies over, and a BBC broadcast describes the crash and Hero's role, the nature of the "secret" mission is questioned, and there is concern that the Singapore operation may be hazardous. Napier is tasked with the job, and decides to take Fuller on the grounds that he has been proven with his fire rescue, for which he received the George Medal (Napier also has a George Medal for a bomb disposal job). Napier and Fuller leave Hero, unarmed, and collect a rental car. They are immediately attacked, but manage to escape, and a car chase ensues. They leave the car at a rural village, from which they eventually make their way back to Hero, after being shot at. Corbin unexpectedly arrives on Hero, having flown from Hong Kong. Holt accuses him of setting up the operation to fail, and is angry that his crew members have been put at risk. Corbin says they did well, but is shocked when Holt tells him that the papers were safely returned to Hero. Holt asks him to apologize, which he does very reluctantly. Holt then admits that he had ordered Napier to dump the papers in the case of trouble, and thanks to his concern for Fuller's child, he had obeyed.

Hero visits the (apparently fictional) island state of Locloon (sp?) on a visit intended to help the UK's chances of handling the exploitation of a newly discovered oil field. The officers (and Zoe Carter, looking for a story) attend a reception hosted by the influential but strict Zee Khay Lim, where Peek meets and quickly falls in love with Zee's daughter Akiko. Things are not going well for British interests, with the unenthusiastic Consul Cobbold expecting the deal to go to the Americans, and Zee saying he's impressed only by honourable behaviour. There is tension between Holt and Napier when Holt thinks Napier is becoming romantically involved with Carter, and Carter becomes angry at Holt when she discovers his attitude. Peek wants to marry Akiko, and Akiko asks him to smuggle her on board Hero, since she has no way of escaping her father's influence and an unwanted arranged marriage. Peek discusses her with Holt, but Holt says they can not ignore local customs and cause a diplomatic incident. Peek asks Midshipman Vidler to tell Akiko that he was unable to meet with her as planned. Holt sends a gift to Carter as reconciliation. Hero leaves port, but Akiko is discovered in a spare cabin, having been brought aboard by Vidler after Akiko told him about her situation. Holt orders Hero back to Locloon, where she is returned to her father. Her father reveals that she had been lying all along: that she is younger than she had claimed, 16, has no marriage arranged, and was trying to reach an ensign from an American ship which had visited recently. Zee is grateful for her return and agrees to help the UK reach a deal on the oil.

Hong Kong businessman Victor Chelten escapes from a mental hospital and goes on the run, shooting two men in the process. Hero is assigned to help the police, led by Chief Inspector Grainger, as they search the outlying islands. Kiley knows Victor and his wife Jenny, who he is in love with, although he hasn't seen her since she married Victor 10 years ago. He arranges to meet her, and she tells him that she thinks the police intend to kill Victor, but he'll be hiding on Han Hing Island. Holt exchanges information with Zoe, who says Victor has been known for women, alcohol, and drugs, until having a complete breakdown, while there has also been gossip about Jenny having an affair, which Kiley refutes indignantly. Kiley reveals Victor's location to Holt, on the condition that they land without a police squad and that Kiley can try to talk to him. Meanwhile, Zoe is interviewing Jenny, and reveals that Victor was divorcing her due to her affair with a penniless young army officer, and she would stand to gain financially if Victor died before the divorce. Victor confronts Kiley on the island, telling him he has been fed up with his wife telling him for 10 years that she should have married Kiley instead, and when Grainger arrives, threatens to shoot them both. However, Napier and Fuller arrive, and Fuller shoots Victor dead with his rifle. Kiley arranges to meet Jenny, but just watches her from a distance.

Hero and Army Air Corps helicopters rescue a young and apparently wealthy Chinese woman, alone in the ocean. She apparently doesn't speak English, and Hero takes her to Hong Kong. She is taken away by a police inspector, who later says that she is Lily Tan, a singer at a Wan Chai nightclub. She had claimed that she had fallen into the sea at the waterfront, which Peek says was inconsistent with where she was found. Holt, Napier, and Carter attend the opening of a youth centre, on request of the Governor at short notice. The centre was a gift from Henry Witzel, a wealthy and reclusive American living in Hong Kong, who invites them back to his mansion for a reception. There, he praises Carter's work and offers to be interviewed the following day, which is unprecedented. That night, Holt and Carter visit the nightclub and watch Tan perform, and overhear her accepting a gift from somebody unseen. They note that she can speak English perfectly well. Carter arrives at Witzel's home for the interview, and observes Tan storm out, apparently after an argument, while Witzel is alone inside. Back with Holt, she speculates that Tan was Witzel's mistress, and that apparently something sinister was going on and Witzel was keeping tabs on what they all knew. Holt discovers that Witzel owns a yacht, which was at sea on the day they recovered Tan, while Carter follows Tan and discovers that she lives in a luxury apartment on Repulse Bay Road, owned by Witzel's company. They speculate that Witzel had attempted to murder her, by dumping her at sea, and that she was now attempting to blackmail him. Concerned about her safety, Holt decides to confront Witzel at his home. After telling Witzel his theory, Witzel and his wife reveal the truth, that Tan was their adopted daughter, and had gone sailing alone in a hired dinghy after Witzel had refused to lend her his yacht, and had suffered an accident at sea. They had only been arguing about her new boyfriend, who was in the shipping business; he turns out to be MAA Harry Burnett.

Hero is sent to a fictional British Overseas Territory – Eddowes Island – at the time of its handover to an unnamed Latin American country. Eddowes is described as being 50 miles offshore, and the islanders are stated as being offered a choice between retaining British nationality and leaving, or staying and becoming citizens of the unnamed country. The tensions this caused amongst islanders, the ship's company – one of whom (Leading Seaman Anderson) is described as having been born on Eddowes – and British and Eddowes government officials are depicted in a realistic way.

The episode had very strong parallels with the contemporary Falkland Islands situation, and it foreshadowed the events that led to the Falklands War. Much of the episode was filmed on Dartmoor, states the Michael J. Bird website (link below). During filming of this episode, series creator Ian Mackintosh received news that he had been awarded an MBE for his work on Warship.

Hero, while monitoring a Soviet weapon testing ship, recovers an unknown device from the sea, presumed to be a new type of mine. Napier keeps a close eye on it while Hero returns it to port, concerned that it may be booby-trapped to explode on a timer. Incidentally, they also spotted a man on the supposedly uninhabited island Errol(sp). The MoD is interested in the device, but the Home Office is more interested in Errol, since although it was never formally annexed by the UK, they don't want to see it claimed by another state. Hero is ordered to return and remove the man. When they find him, he says he's a Scot named Robertson from Fort William and wishes to be left alone. Some details from his story can be confirmed, and the Home Office is happy to have a British presence on the island. Peek notices that Robertson has a photograph of an attractive woman who seemed familiar. After Hero has left, he finds the same photograph in a magazine, named as Amanda Clark Davis, whose father, Rolland Clark Davis, died recently but the body was never recovered. Holt guesses that Robertson is actually Davis, and returns to Errol in time to catch him leaving the island with Amanda. He had faked his death to collect an insurance payout. Napier, still monitoring the "mine", hears it ticking, and decides to defuse the device. It turns out to be a decoy left by the Soviets to encourage Hero to depart.