Nora

Nora begins to date a younger man, Simon, an oncologist who volunteers at her cancer shelter - however Sarah and Kevin become suspicious after they discover he was sued twice as a doctor and believe he had his license taken away. After Nora gives him a sizable amount of money, he apparently loses interest in her and tells her he has to travel for a few weeks. Upon his return, Sarah tries to convince her mother that Simon is up to no good, but it turns out Nora is already aware of this and hands him over to the police. Nora also spends time taking care of Kitty as she, along with her husband Robert and son Evan, move in with Nora during her cancer treatments. Dennis York, an old associate of William's, reappears and blackmails Nora with a secret she has been keeping that could tear apart her family. He agrees not to reveal this secret if she convinces her children to sell their shares in Ojai to him. While trying to talk her children into agreeing, Nora brings Tommy home to talk to Sarah, who is most against selling the company. Nora eventually reveals that she and William had been paying off the family of a young boy who became paralyzed after a fight with Kevin.

She and Holly also investigate York's reasons behind wanting Ojai when the company is in such financial trouble and believe the answers lie in land that William purchased called 'Narrow Lake,' which is later revealed to be an anagram of 'Nora Walker'. In the episode 'Lights Out,' Nora and Sarah discover that William was planning on building Nora a house on Narrow Lake.

Nora keeps secretly drilling at Narrow Lake, despite Sarah being skeptical. It's revealed that beneath Narrow Lake lies a water main, and now Ojai will become a water company.

Kevin & Scotty

Kevin and Scotty hope for a baby and decide to look into surrogacy. They continually disagree on the ways in which to approach it, especially when it comes to decisions involving their surrogate, Michelle. Scotty learns his father had an affair and is divorcing his mother. Soon after, Scotty must leave his job, as his restaurant hits financial trouble and must be closed down.

After Robert decides to leave office after his term ends, Kevin becomes unemployed and takes some time to decide what he wants to do with his life. He discover that when Kevin was a teenager and struggling to accept he was gay, he started a fight with a boy, Aaron, who tried to kiss him, resulting in him falling off a platform at Ojai. Although William and Nora told Kevin that Aaron was fine, it is revealed in 'Time After Time' that Aaron is in fact paralyzed, and William and Nora have been paying his family ever since. This creates a massive strain in Kevin's relationship with his mother, although they begin to re-bond on his birthday. Kevin and Scotty also discover their surrogate is pregnant.

In the episode 'Love All,' Scotty and Saul begin to make plans to open their own restaurant, while Kevin begins to feel unhappy with being unemployed. He tells Scotty to go forward with the restaurant while he figures out his purpose.

In the season finale, Scotty is hosting a dinner with the family revealing his new menu. While preparing in the kitchen, Saul discovers that an old partner of his is living with AIDS. Scotty and Kevin tell Saul that they get tested every year and that he should, too. Saul is defensive because he hasn't been sexually active in years and feels that he doesn't need to. Yet, Saul gets tested, and while waiting for the results, he blows up at Scotty and Kevin. He tells them that when he was growing up, the world was a lot less accepting of his lifestyle. Later on, with Nora by his side, Saul calls for his results and tells her that he's negative, and that he'll be okay. In the final car crash scene, after Kevin sees that Scotty is okay, he goes to Saul to see if he's all right. Saul has blood on his hands and face, but tells Kevin not to come closer, that he can't come closer and touch him, implying that he is HIV positive.

Kitty & Robert

Kitty and Robert's marriage is still damaged from the events of the last year; however, after Kitty discovers she has stage 3 lymphoma, their relationship begins to heal. Robert, supported by Kitty, continues to run for governor as she begins chemotherapy. Shortly before Justin and Rebecca's wedding, Kitty goes for an MRI scan that reveals that the chemotherapy has not worked and the tumors have increased both in size and quantity. At first, she lies to Robert and insists that the results will not be ready until after the wedding; however, she collapses during the ceremony and is taken into the ER, where it's discovered she has a clot on her lung and the cancer is becoming more aggressive. The doctors inform her that her only real chance is to undergo a bone marrow transplant and she must look to her siblings to find a match. The only match is Ryan, who initially refuses. Later, he appears at the hospital and agrees to donate his bone marrow, because he does not want Evan to grow up with an absent parent like him. The transplant is a success, and Kitty enters remission.

Robert agrees to drop his gubernatorial campaign at the same time that Kitty begins talking to Buffy, an old friend, about returning to a life in politics. After Kitty tells Robert, he thinks she should run for his seat. They put the decision to a family vote. After some initial hesitation from Kevin, who is unsure of his future in the job, they all agree that she should run.

Toward to end of the season, Robert begins collecting evidence against a politician named Stanton and gains the suspicion of Kevin. Although Robert promises he is doing nothing dangerous or unethical, once Stanton catches on to what Robert is up to, Stanton threatens to ruin Kitty's career if Robert goes ahead with his information.

Kitty begins campaigning, bringing Nora and Sarah along. Robert has taped proof of Stanton earning money off the backs of American soldiers. He refuses to release the tapes because Stanton threatened Kitty, but he will keep them safe. Meanwhile, Robert speaks to Justin secretly and gives him the key to his safety deposit box. An envelope is inside. Robert tells Justin that if anything happens to him, he should give the key to Kitty and she'll decide what to do with it. Justin notices a certain medicine that Robert is taking and it looks serious.

Lies about Kitty end up on the Internet. They said Kitty was campaigning in a private jet paid for by the tax payers, and that her wig cost $4,300, which is unnervingly accurate.

At dinner at the Ojai House, Justin confronts Robert about all the secrecy and his medication. Robert says that he's been having more complications with his heart. Justin feels like he can't keep all of this a secret. So Robert asks for the key back because he can't trust Justin. Before Robert gets the key, they're interrupted for dinner. At dinner, Robert starts feeling dizzy and asks for an ambulance. At the hospital, Robert finally tells Kitty what he's been up to. On the car ride home, Kitty tells him that he should release the tapes to get at Stanton.

In the final scene, Kitty and Robert's car hits a truck. Kitty is okay, but Robert is hurt badly. She calls for Justin, but Robert tells Justin to go help Holly and that he'll wait for the ambulance. Robert is fading, and Kitty tells him to talk to her. He tells her that she was right about his being afraid that he couldn't keep up with Evan after his heart attack. He tells Kitty how strong she was when she held Evan in his arms. Robert begins to fade, and then he stops talking and it ends with him in a coma.

Justin & Rebecca

Justin begins an accelerated medical school program and is paired with a highly intelligent, but socially challenged, lab-partner named Carter who makes Justin feel bad for not doing as well in school because of Justin's family obligations. As Justin and Rebecca prepare for their wedding, their relationship becomes strained when she discovers she's pregnant. Seeing the pressure he is already under from his studies, Rebecca initially decides not tell him but finally does just as he finds out he has not done well on his mid-term exams and is put on academic probation. During his bachelor party, Justin breaks and drinks a glass of champagne, rows with Kevin and storms out while Robert tells the other Walkers that Rebecca is pregnant and that they should support Justin. At Nora's, Justin confides in Rebecca that he had a drink and is worried he is out of control of his addiction. At a Narcotics Anonymous meeting, he confides that he is having his own doubts about marriage and fatherhood but loves Rebecca, not knowing that her father is in the back of the room. Justin does not show up to the wedding rehearsal leaving Rebecca thinking he has changed his mind. In fact, he witnesses a small boy being hit by a car and goes to his rescue which makes him realize how much he wants to be a father and her husband, and rushes home to tell her this. They are later just about to be married when Kitty collapses at their wedding.

Soon after this Rebecca suffers a miscarriage, devastating her and causing a rift between her and Justin when she avoids spending time with him and talking about what happened. But, after they begin to communicate they become close and move past losing their baby. While investigating Narrow Lake with Holly, Justin sees a Marriage Hall and tells Rebecca they should get married right there and then because after everything that's happened, he doesn't want to wait any longer. They spend their honeymoon at the Ojai Ranch, where the entire family turns up to celebrate.

After discovering one of his friends went back to the war and was killed, Justin begins to feel uncertain about his future in medicine and tells Rebecca he wants to feel part of a team, as he did when he was a soldier. This leads to Justin suggesting they move to Haiti for a year with a medical student program, allowing him to help those in need and Rebecca to continue her passion for photography. Rebecca, however receives a job offer at one of Ojai's rival companies following the closing of Ojai.

Rebecca tells Justin that she accepted the job offer. Justin feels that Rebecca has made the decision for them not to go to Haiti. Rebecca suggests that as a compromise, she could stay here and Justin go to Haiti for a year, but Justin says as newlyweds they should be together. After dinner at the Ojai House, Justin asks Rebecca if she was serious, and she says yes. She wants them both to be happy and not resent each other. In the final scene, Justin and Rebecca are the last to arrive at the car pile-up. Justin rushes around to help as many people as he can, while Rebecca looks for Holly. She finds Nora who tells her she can't get Holly out the car. Rebecca calls Justin over as he attempts to help Robert. He's able to wake up Holly, and wrap his jacket around her.

Sarah

Sarah is briefly seen in the premiere explaining she has endured a terrible summer of online dating and retreated to France for a much-needed vacation. She lands back in California with a new French beau, Luc, who helps her question her view on men and relationships. After living together for a short time, he decides to leave again after realizing his free-spirited attitude and her corporate and family lifestyle do not work together. Sarah then meets a single dad at Paige's science fair and the two hit it off. Just as their romance heats up, Sarah receives contact from Luc and realizes she still has feelings for him. After ending things with Roy, she and Luc resume their relationship which hits yet another obstacle as Luc finds it difficult to renew his visa and faces being deported. In the episode 'Where There's Smoke', Luc wins the lottery to get a green card, however now that their lives have become real the couple begin to have problems, especially concerning Cooper who has been acting out. Luc tells Sarah he needs to define his own relationship with the kids.

Sarah is depressed after Ojai closes. She sits on her couch for three days eating pizza. Nora has her go on the campaign bus with her and Kitty. Throughout it, Sarah drinks wine and watches soap operas. Later, Sarah gets a call from Holly and they sit down and discover the water main at Narrow Lake, which she, Nora, and Holly have ownership of. Ojai will now be a water company. In the final crash scene, Sarah is shown to be okay and calls 911.

Tommy

Tommy comes home from Mexico and reveals he and Julia are getting a divorce and he has not spoken to Elizabeth in months. After talking to Kitty and his mother, he decides to go to Seattle to restore his relationship with his daughter. He briefly returns with Elizabeth, breaking the terms of his custody agreement by crossing the state-border for Justin's wedding. Kevin contacts Julia and tells her what Tommy has done and convinces Julia not to call the police. But, then Julia turns up at the Walker house during the wedding rehearsal and demands that Elizabeth leave with her because she cannot trust Tommy anymore. She stays with Kevin and Scotty for the night and relents, allowing them to take Elizabeth to the wedding and see Tommy.

Tommy returns once again and stays with his mother as he helps her deal with Dennis York. After Tommy tries to extract information from York, along with Kevin and Justin, York retracts his offer. Tommy helps the rest of the family sell off Ojai assets and, with Sarah, organizes its closure.

Ryan

Ryan begins the season plotting with Dennis York to bring down Ojai so Ryan could get revenge on William for what he believed William did to his mother. Ryan sabotages the wine storage machines, thereby destroying Ojai's award-winning product and making it impossible for the company to be saved from financial ruin. Ryan is caught by Holly, who threatens to turn him into the police. However, Saul intervenes and Ryan is spared from criminal charges. Ryan's last storyline involves him donating his bone marrow to Kitty after she collapses at Justin and Rebecca's wedding, and attempting to come to peace with the Walkers. The character's last appearance is in "A Bone to Pick," and following that episode the character vanishes without explanation. In an April 2010 interview, David Marshall Grant, the Brothers and Sisters show runner, stated the Ryan character was not working within the context of the show, and the character would not be returning.

Ojai Foods

Holly discovers most of her financial investments have vanished, due to a fraud scandal and she is thus much less wealthy than she thought. This position leaves Ojai in trouble, so she suggests creating a new low-priced wine 'Coastal Reserve' to save the company. Dennis York, a man from William Walker's past, persuades Ryan, who is still furious with William, to join him in gaining control of Ojai behind the Walker family's back. Ryan shares confidential information with Dennis and destroys the stock of the new wine. After discovering this, Holly begins questioning why Dennis would want to take over a financially struggling company, leading her to investigate the true value of Ojai.

Dennis York blackmails Nora into convincing her children to sell Ojai to him, which leads Nora to join Holly in investigating the company's hidden worth. Rebecca gives the company her $2 million savings giving the family time to discover the secret. Although the family begins to agree it may be time to sell and let go of the company, Dennis York retracts his offer. Ojai is officially closed in the episode "Lights Out," but at the same time, Nora and Sarah find plans which show that William was planning on building a house for Nora on Narrow Lake. Nora pays for a few days further drilling at Narrow Lake and, in the season finale, they discover a large water reserve.