The gang helps Brandon repair the Walsh house after it falls out of escrow, and Steve decides to move in with him and Valerie. Kelly prepares to celebrate her 21st birthday party at the Greek Concert Hall with the gang. Ray becomes the prime suspect in the theft of money and several jewelry items from Donna's parents and others. But Valerie exposes Ginger as the culprit which at the end is revealed to be a scam for the gang to get to like Valerie again. Meanwhile, Dylan goes off in search of the mobster, Anthony Marchette, who was the mastermind of his father's death and decides to commit himself to a personal revenge against him.

Kelly, Donna, and Clare decide to take a "just girls" road trip in which Valerie spoils their fun by insisting that she come along. Soon, the trip becomes unpleasant when secrets from their pasts come into the light with Valerie admitting that she has feelings for David, and that she seduced Ray months earlier for no reason aside from the ultimate thrill of it. Donna becomes angry at Valerie, and then at Clare who admits she knew but did not say anything. In a turn of events, the four of them end up stranded for the night in convent after their car breaks down. Valerie also convinces Donna to break up with Ray knowing that he is physical abusive. Back in Beverly Hills, Steve rents out the Walsh house (Casa Walsh) to a movie crew to shoot a porn flick. Meawnwhile, Toni's father comes face-to-face with Dylan over him seeing her. Also, Brandon and Susan's relationship heats up even more.

A major earthquake hits L.A. which traps Susan and Brandon in an elevator with a pregnant woman who goes into labor. Meanwhile, his friends are rocked after Dylan's announcement about his and Toni's engagement. While Donna continues to try out for Rose Queen, she finds a picture of her mother taken during a 1969 Rose competition, while at the same time, Ray's therapist warns Donna that he has a history of being abused as a child by his father and he may harm her.

On the eve of Dylan and Toni's wedding, Marchette sends his thugs to kill Dylan to prevent it from happening. But gets thwarted by the gang's plans for the happy couple. Kelly and Donna throw a bachelorette party for Toni at the beach apartment with male strippers, while Brandon organizes an uneventful bachelor party involving a card game at the Walsh house. The next day, Dylan and Toni finally get married. But afterwords, Marchette requests a meeting with Dylan after failing to dissuade Toni from her marital plans, and plans an ambush to take care of Dylan. Bruno learns about his boss' plans to murder Dylan and tries to warn him. But Bruno's warning comes too late when the plan backfires with Toni taking the bullets by mistake in a drive-by shooting. Meanwhile, Ray threatens Donna after she breaks up with him to attend the wedding with Joe Bradley... just as Ray's therapist had warned her.