Brenda and Donna attend an animal rights rally, and are crestfallen when the university refuses to suspend animal testing. After Rocky dies of cancer, Brenda becomes involved with a small group of radicals. She serves as lookout when the group breaks into the university research building and tries in vain to save Andrea's lab (which does not harm animals in its testing). Brenda is arrested. Kelly and Brandon are furious when Dylan refuses to fund Lucinda's film. He finally tells Kelly that Lucinda came on to him. Brandon breaks up with Lucinda and Kelly confesses her kiss with Brandon. Dylan races over to the Walsh house to fight Brandon, but the tension is defused when he accidentally punches Steve.

Emily flies back from Paris to attend a seminar at La Jolla. She asks Brandon to meet her at the airport, claiming to have just a four-hour layover. She actually has a week until the beginning of her seminar, but Brandon breaks her heart by revealing that he is dating Kelly. When he sees her back to her hotel room, they share a passionate kiss. Steve and Griffin organize a holiday rave at an abandoned house. Valerie helps them out in the hopes of getting back in Steve's good graces. David and Clare accidentally post the notice about the event on a computer bulletin board for lesbians, who constitute most of the guests. The house has very poor wiring and continually blows fuses. Griffin uses too much electricity, and the house catches on fire. Ray rescues Steve and Valerie, who were fooling around in one of the bedrooms. Kelly and a girl named Allison are trapped in a downstairs bathroom with no means of escape. The firefighters try to reach them as they are engulfed by flames.

Kelly delights in telling Brandon about Valerie's pregnancy and abortion, and also shares her doubts about Val's story. Brandon goes to see Kenny, who portrays himself as the innocent victim caught in the web of an evil vixen. He tells Brandon that he paid Valerie $100,000 to stay away. Brandon threatens to throw Val out of the house unless she returns the money. Valerie plans to move out, but instead returns the money following a talk with Tracy. She confesses to Brandon that she was never pregnant, and insists that she cannot live up to his moral expectations. Mel, worried by David's newfound wealth, asks Donna to keep an eye on him. David goes on a wild spending spree, and later shows up at Donna's apartment in the middle of the night after swimming in the ocean. David offers to help out the financially strapped Valerie by purchasing half of the club. Steve impresses Clare with his dedication as he trains for the crew race. His team barely loses, but Clare decides that she wants him back. Kelly comes clean with Mark about her past drug problem.

During an argument with Donna in the student union, David throws a tantrum and cuts his hand on a glass. He must see a psychiatrist after displaying hostile behavior toward the ER staff. Mel agrees with the doctor's recommendation that David be held 72 hours for observation. David is diagnosed with a mild form of manic depression. His mother comes to see him and advises him to moderate his behavior; he will not require medication if he seeks therapy and stops drinking. David thanks Donna for her support and they decide to get back together. Steve faces plagiarism charges; Professor Randall, who assumed control of the independent study course after returning to CU, recognized Brandon's writing. Randall still holds a vendetta against Brandon and brings collusion charges against him. Kelly and Mark's plans for a romantic weekend getaway are foiled by a lost reservation. They finally secure a motel room, only to come down with food poisoning. The gang helps Willie build a house that his family will receive from Habitat for Humanity. Val displays construction skills as a result of working with her contractor father, but hints to Clare that she has few happy memories of her dad. Everyone eats Thanksgiving dinner inside the unfinished house.