Brenda and Kelly's friendship takes a turn for the worse. Meanwhile, Sean moves in with the Wilson family, Naomi hangs with a new crowd, and Silver becomes jealous when a cheerleader pays a little too much attention to Dixon.
Kelly returns to Beverly Hills, revealing what happened between her and Dylan during her trip. Meanwhile, Annie turns sixteen and gets a surprising gift from Naomi. But that's not the only surprise in store for the Wilson family. An unexpected visit from Harry's biological son, Sean, throws a wrench into their happy family dynamic.
Silver invites a few of her female friends over for a girls' night, but the event quickly turns into a house party. Meanwhile, Debbie and Harry finally reveal to Dixon and Annie that they have an older brother who was given up for adoption long ago.
After recuperating from her health scare, Adrianna returns and tries to make amends with Naomi, but her ex-BFF refuses to forgive her for the betrayal. Adrianna makes a surprising connection with Navid, who helps her through her situation. Meanwhile, Annie and Ethan finally take their rapidly growing romance to a new level during the school's homecoming dance, causing Naomi to feel jealous.
As Silver's "half birthday" approaches, she decides to spend a spooky evening watching movies with her friends at the famous Hollywood Forever Cemetery. Harry's past returns to haunt him when Tracy reveals she is searching for their son. Annie and Ethan are paired up for an assignment, which leads to a connection after the two take care of a baby. Naomi confronts Adrianna as her drug addiction spirals out of control. Meanwhile, Ryan mourns Kelly's unexpected departure.
After Debbie lands the chance to shoot a fashion show for Nylon Magazine, Annie uses the opportunity to her advantage for a class assignment. Naomi believes the upcoming show could help fix her parents' marital mess, but it only makes matters worse. Ty and Annie's relationship is put to the test when Adrianna reveals a secret. Meanwhile, Kelly receives a phone call that could change her relationship with Ryan.
As the opening night of the school musical approaches, Ty reveals to Annie his plans for a one-on-one after party in his hotel room with her. When Annie's dad catches her in a compromising position with Ty, he becomes concerned about how fast their relationship is developing. Meanwhile, Naomi can't accept her parents' divorce and Adrianna is confronted about a substance abuse problem, giving Annie the chance to take the lead in the musical.
Annie, Harry, and Debbie are surprised to learn that West Beverly's theater director can no longer oversee the school musical. Kelly persuades Brenda to take over as the play's director, but they end up arguing over Kelly's involvement with Ryan. Meanwhile, Dixon tries to get a part time job at the Peach Pit and Naomi confronts her father's mistress.
Harry and Debbie plan a family bowling night, but find their plans interrupted by the unexpected arrival of Annie and Dixon's friends. Meanwhile, Annie finds herself torn between Ethan and Ty, Naomi experiences a difficult evening with her father, and Kelly and Silver learn that Jackie's drinking is beginning to spiral out of control.
In part two of the series premiere, Naomi finds herself in trouble when she fails an assignment, and Ryan and Kelly bring the issue to Harry\'s attention. Meanwhile, Dixon must deal with jealous teammates on the lacrosse team and Annie meets a potential love interest.