Christy has a hard time juggling the workload at law school, her job at the restaurant, and going to meetings. She considers quitting school until a new AA attendee gives her perspective about overcoming obstacles. Elsewhere, Adam gives Bonnie permission to plan their wedding any way she wants, but she soon realizes that she wants him to be involved after she dreams he's having an affair.

With very little time in her life to get her studies done, Christy considers quitting Gambler's Anonymous, thinking she doesn't need it because she's only had three incidents in her life. Bonnie disagrees with her daughter, and turns out to be correct when Christy gets a good-sized check for incidentals as part of her student loan and finds herself in a casino parking lot.

Absent: William Fichtner as Adam

Bonnie tries to trick Adam into choosing the outdoor venue she wants for their wedding by showing him an old barrel factory as an alternative, but it backfires. Although Adam agrees to Bonnie's wedding site, he uses his life savings to buy the barrel factory with hopes of turning it into a bar. Meanwhile, Christy learns her strict law professor, Natalie (Constance Zimmer) is a fellow alcoholic.

After Tammy Diffendorf (Kristen Johnston) is paroled, Bonnie invites her to stay at the apartment instead of going to a halfway house. As Tammy struggles to integrate into free society, she starts to affect those around her, particularly Christy and Adam.

Marjorie's husband Victor dies after another stroke, yet she does not seem as upset as Christy thinks she should be. Marjorie later admits that her first feeling after Victor died was relief, and she scolds herself for it. Wendy tells her that when someone passes who was ill for a long time, the survivors often already mourned for them. Marjorie finally breaks down while holding Victor's favorite cat.

When Tammy takes on a loud home improvement project at the apartment, Christy spends time at Jill's house to get her studies done in peace. However, Christy gets mad when she sees what Jill does with the $75 payment on her gambling debt. Meanwhile, Bonnie talks Adam into both of them getting tattoos, later getting somewhat addicted to being inked.

Absent: Beth Hall as Wendy

Christy and Wendy agree to help Jill clean out her huge walk-in closet with hopes of scoring some nice items for themselves, but the process reminds a dejected Jill of all her failures. Elsewhere, Bonnie invites a lonely Marjorie to spend time at the apartment, where they do a jigsaw puzzle with Tammy. Seeing Marjorie needing companionship with Victor gone, Bonnie suggests that Tammy move in with her.

Absent: William Fichtner as Adam

One of Christy's study partners mentions a podcast she listens to about "the nightmare of all mothers". Christy decides to listen to it, and learns that it is Violet speaking about her. Christy appears on the podcast to share her side, but it does little to reconcile herself with Violet. Elsewhere, the opening night for Adam's bar is not very successful after Bonnie invites a bunch of non-drinkers from AA.

Special guest star: Sadie Calvano as Violet. This was Calvano's last appearance on the show.

Christy uses past experiences to face off against the best student in her class in a mock trial, with hopes of earning a summer internship with a local law firm. Though Christy wins the case, the internship still goes to her opponent. An angry Christy confronts the law firm rep, who says he passed her over for the internship to offer her a paid position instead. Meanwhile, Tammy has dental surgery that leaves her in pain, forcing Bonnie to manage her pain medication.

After bumming a cigarette from Chef Rudy, Christy finds herself developing her old smoking habit. Elsewhere, Tammy goes on her first date since getting out of prison, but gets conflicting advice from Bonnie and Jill.

Special guest star: French Stewart as Chef Rudy

Absent: William Fitchner as Adam

When the ladies from AA decide to participate in a Secret Santa gift exchange, Christy goes to great lengths to surprise and delight Wendy. Meanwhile, Bonnie tries to help Tammy find a job and prevent her from being sent back to prison, and Adam tries to hide from Bonnie the fact that his bar is losing money.

Marjorie, Jill, Wendy and Christy take a road trip to see a woman who is famous for her hugging therapy, but Christy's smoking habit causes her to lose their tickets. Meanwhile, Bonnie and Adam disagree about ideas to save the bar from financial disaster.

Adam's friend Mitch (Bradley Whitford) is in town to make amends to Christy and Bonnie, who reluctantly accept his apologies. Mitch claims to be sober, saying it caused his breakup with Leanne (Nicole Sullivan) when she refused to stop drinking. But on his first visit to Adam's bar, Mitch is back to his old ways.

After a break-in at Jill's house, a police officer named Andy (Will Sasso) is assigned to guard the place for a few days. Despite their differences, the two divorcees bond and Jill starts to enjoy having Andy around. Meanwhile, Christy becomes frustrated when Nora doesn't offer much validation of their sponsor-sponsee relationship.

Absent: William Fitchner as Adam

At a Valentine's Day dinner with Bonnie, Christy laments her empty love life and blames mom for her lack of trust in men, but Marjorie (whose plans to watch Notting Hill keep getting interrupted by pleas for advice from her friends) clues Bonnie in and the situation ends on a much nicer note. Jill goes on a first date with Andy, but Andy later leaves after overhearing Jill tell one of her highbrow friends that Andy is just her security guard and not a date. Tammy has sex for the first time in seven years while riding with Yuri.

Absent: William Fitchner as Adam

When Christy gets her credit card bill and sees how much she spent on cigarettes, she tries to quit, making her irritable around the rest of the group. Tammy encourages Bonnie to take the GED exam with her, but Bonnie fails. After Bonnie describes to the group how she felt while taking the test, Wendy suggests she may have Attention Deficit Disorder.

While helping Adam at the bar during the March Madness rush, Christy gets caught up with a group of guys using phone apps to bet on every aspect of the games. Although Christy doesn't make any bets herself, she receives tip money for making correct picks for the guys, causing her to ask her GA sponsor if it counts as gambling. Meanwhile, Bonnie is at her prickly but vulnerable best during her first sessions with her new A.D.D. therapist, Trevor (Rainn Wilson).

Bonnie gives up a chance to go with Adam to an Eagles concert so she can take care of Christy, who has a bad case of the flu. However, the challenge of being a mother to a sick child soon wears on Bonnie. Meanwhile, Jill, Marjorie, Wendy and Tammy notice a change in their group dynamic with the Plunketts' absent.

Christy and Bonnie are surprised to open the refrigerator and find plentiful, name brand food, which Adam says he bought because the bar is doing well. Adam then surprises Bonnie with a new car at Baxter's dealership, but Bonnie refuses it because her decades-long experience tells her that good fortune never lasts. Elsewhere, Tammy encourages Christy to go on a date with Yuri's cousin, Sergei. Christy likes the guy until she sees him getting involved in some criminal activity, which she fears might affect Tammy's parole status. Christy tries to convince Yuri to throw his cousin out for Tammy's sake, but instead, he breaks up with Tammy.

Special guest star: Matt Jones as Baxter. Jones' final appearance on the show.

Bonnie and Tammy take a trip to their old foster home to make amends to their former caretaker, Claire (Lois Smith). Angered that Claire blatantly favors Tammy, Bonnie confronts her, only to discover a secret about Tammy's troubled past. Elsewhere, while Marjorie and Wendy attend a play at the senior center, Christy and Jill hesitantly accept a coffee date with a pair of men from their Tuesday meeting. While the two women return from the date, Christy's car is stopped by Andy, who reconnects with Jill.

Absent: William Fitchner as Adam

Despite owning a new car and having no place to park her old one, Bonnie is procrastinating on selling her old beater and being harsh to Adam when he tries to talk to her about it. Her ADD therapist, Trevor, tries to convince Bonnie that the car represents her old self, which she has grown out of but is hesitant to leave behind. Meanwhile, Christy is annoyed that her new law firm job involves grunt work and being ignored by a jerk of a junior associate, but later finds perverse pleasure in coming up with a sharp legal idea that the jerk passes off as his own work.

Special guest star: French Stewart as Chef Rudy

On the day of her six-year "sober birthday", Christy is distraught after learning that Nora is moving to Minneapolis and can no longer be her sponsor. Elsewhere, Adam and Bonnie travel to Reno to pick up a vintage jukebox for the bar, and argue over Bonnie's reluctance to set a wedding date. Bonnie then angrily agrees to marry Adam immediately at a chapel in Reno, which further upsets Christy when the two return. Christy complains that her mother has shared terrible experiences with her, but cut her out of a wonderful one. Everyone gathers at the bar for a much nicer celebration, and Marjorie tells Christy she'd love to return as her sponsor.