Naomi finds herself in trouble when she fails an assignment, and Ryan and Kelly bring the issue to Harry's attention, while Harry struggles with a disturbing revelation about the result of a secret tryst with Naomi's mother, Tracy, from many years ago. Meanwhile, Dixon learns more about Navid when they team up to try to pull a school prank against Palisades High. Annie meets a potential love interest in the form of drama student Ty Collins, who turns out to be the wealthiest student at West Beverly, and who spirits her away for San Francisco for the evening. Silver posts the story about Ethan's infidelity with Naomi on her Internet blog, while Adrianna continues her self-destructive slide into drugs and debauchery. Also, Ryan tries to ask Kelly out on a date, but she has to find a babysitter first for her four-year-old son, and former West Beverly alumni Brenda Walsh, now a successful Broadway and London theater director, arrives back in town to help put on a new school play.

Annie and her parents, Harry and Debbie, are surprised to learn that West Beverly's theater director can no longer oversee the school musical. Tabitha offers to direct the musical play, but her eccentric and demanding attitude does not sit well with Annie or the other actresses. Kelly persuades Brenda to take over as the play's director, much to Tabitha's chagrin. But Kelly and Brenda end up continuing to argue over Kelly's continuing involvement with Ryan and taking up time with Kelly's son, Sammy. Meanwhile, Dixon tries to get a part time job at the Peach Pit coffee shop to get money to pay off a bully after Dixon accidentally dents the bully's car. Naomi becomes more distraught over her parents, Tracy and Charlie's, open-marriage arrangement, and she eventually confronts her father's mistress to show her true anger towards her. Elsewhere, Annie's growing relationship with Ty is the talk of the school, which leads to Ethan, who's growing more uncomfortable and jealous, to try to get her attention.

As opening night for the school play nears, Harry catches Annie kissing Ty, which makes him worry that she and Ty are moving too fast with their growing romance. Silver, stressed out from her job as the stage manager, gets some comfort from Dixon. Meanwhile, Naomi tries make her mother and father get back together, but Tracy's mind to divorce Charlie is made up. On the opening night of the play, the star Adrianna's drug use comes to surface from being under constant pressure from her overbearing mother, Constance, and when Brenda discovers this, she replaces Adrianna with Annie in the lead alongside Ty. But when both Brenda and Kelly confide in Constance about her daughter's drug abuse, Constance (a secret drug abuser-in-denial herself) refuses to believe them. Afterwards, Adrianna successfully gets her revenge when she manipulates and breaks up Ty and Annie's romantic get-together at a celebration party at a local hotel.

Adrianna and her evil-witch-mother, Constance, plot a cruel revenge against Annie and the rest of the faculty at West Beverly whom they think cheated Adrianna out of her role in the school play. Debbie's boss, Antonio, offers her a job to shoot a fashion show for Nylon Magazine during Fashion Week, where Annie uses the opportunity to her advantage for a class assignment, while her father advices her to try to make amends meet with Adrianna in order to try to catch her in the act with her substance abuse. Naomi believes the upcoming fashion show could help her parents' marital problems and she plans with Ethan to try to break up her father and mistress and have her mother, Tracy, meet with Charles, but it only makes matters worse. Ty and Annie's relationship is put to the test because of Adrianna's meddling. But when Adrianna lets her guard down and reveals to Annie that she lied about hooking up with Ty to break them up, it results in Annie declaring war. Silver is pursued by Debbie's sleazy client, Tony, to work in modeling, while a jealous Dixon becomes aware about what's going on, while Navid feels like he's the 'third wheel' to Dixon and Silver's growing romance. Meanwhile, Kelly receives a phone call from Sammy's father that could change her relationship with Ryan when she's offered to move to Wyoming to join Dylan, while Brenda, with her work at West Beverly finished, plans to return to New York.

Harry and Debbie welcome Sean into their home, while Dixon, Annie, and Tabatha welcome him awkwardly despite the fact that they don't know much about him, while Naomi and her mother, Tracy, welcome him to their home as well. Meanwhile, Kelly and Brenda's friendship is slowly fading away and gets wider after Brenda is hospitalized from an accident and confides in Kelly that she seduced Ryan weeks earlier. Naomi decides to hang out with a new group of girls at school despite Ozzie's advice that they want nothing to do with her. Also, Silver feels threatened when a cheerleader, named Christina, shows too much interest in Dixon who shares the same interests he does.

Annie overhears Sean in a suspicious conversation with someone over the phone, which raises her uncertainty about whether Sean really is who he claims to be. Meanwhile, Brenda tries to make amends meet to Kelly after confessing about a tryst she had with the departed Ryan Matthews. But Kelly and Brenda have to team up to accompany Adrianna to a group therapy session for recovering addicts where after she learns that a friend of hers is HIV-positive, Adrianna goes to a clinic to get tested, but receives some other potentially life-changing news. Elsewhere, Christina invites Dixon over at her house for a Gospel gathering where she makes a startling revelation to him which could shake his romance with Silver.

Adrianna and Navid are forced to make an impromptu exit from the prom when Adrianna goes into labor. Brenda Walsh shows up at the hospital to lend emotional support as Adrianna's labor gets more difficult. Harry and Debbie also turn up at the hospital with Kelly to lend emotional support to Adrianna when she decides to give her baby up for adoption. Across town, in defiance of Harry's orders not to throw any post-prom party, Naomi and Liam decide to throw a party in Jen's house, which she does not approve of. There, Dixon confronts Ethan about Silver when he notices that Ethan might be developing romantic feelings for his girlfriend. When Liam arrives late for the party, Jen takes advantage of his rebellious state. However, Naomi confronts and accuses Annie of seducing her boyfriend. Beaten up and humiliated, Annie leaves the party in a rage. Later, while driving home, Annie runs over someone with her car in a hit-and-run. Liam later decides to confess that it was Jen who seduced him and not Annie. He is unfortunately grabbed by parole officers and sent away by his stepfather to a military academy. Jen is left behind to claim herself as Naomi and everyone's savior... with no one suspecting her true nature.