At a reunion party at the Beverly Hills Beach Club, Clare is stunned after she learns of Steve's past relationship with Kelly, who learns there's more to the story than she knew. Meanwhile, Kenny puts a social spin on his business with Valerie, who once again throws romantic common sense to the wind. David's new friend, Mark Reese, needles Brandon into joining the college TV station. Donna meets an old high school friend whom she once has a crush on. Also, Steve's annoying stepbrothers, Ryan and Austin, return and learn another hard lesson in finding girls.

Brandon is given the request of escorting Lily, Joan's wild and crazy teenage daughter, prior to hers and Nat's wedding, which has a sudden change of venue when a very pregnant Joan goes into labor. Meanwhile, Kelly volunteers to do community service work at an AIDS hospice and befriends Jimmy Gold, a gay AIDS patient whom she is assigned to work with. David moves in with Mark at his house in the Hollywood Hills and later becomes discouraged when he learns of MZA's decision to dismiss him. Also, Valerie is frustrated when Kenny's wife suddenly shows up, disrupting their romantic plans.

Brandon and Mark find the perfect newscaster - a student named Tracy Gaylian - for the campus TV station, but she panics and gets drunk prior to her debut. Meanwhile, an accident with Jimmy gives Kelly a big scare about having AIDS. Mel withdraws David's financial support after learning from Donna that he dropped out of college to concentrate on his film making career. Elsewhere Valerie continues her secret affair with Kenny, who must find the time to be with her.

Steve's so-called "harmless prank" of streaking with his fraternity pledges for Spirit Week lands Brandon in trouble. He refuses to give a video tape of the event to Chancellor Arnold, knowing it will incriminate Steve, while Tracy decides on a crafty plan to get Brandon off the hook. Meanwhile, Donna becomes chairperson of the rush committee for ALPHA sorority and lobbies to get a female jock, named Dani, accepted. Kelly takes a sickly Jimmy on a religious journey to explore his Jewish roots before he dies. David returns to school at California University, but finds all the classes he wants full, and he even has a run-in with Olympic champion gymnast Kerri Strug. Also, Kenny shows Valerie his new apartment for her to live in, but Valerie becomes angry and upset when he breaks a dinner date with her in order to go out with his wife and young son whom he continues to hide his tryst from them.

David and Mark throw a big party at their Hollywood Hills house, until a huge brush fire stops the party which brings back a bad memory for Kelly over the house party fire (back in Season 5) and puts Donna in jeopardy when she attempts to save a baby deer. Steve's flirtation results in serious consequences from Clare, while Brandon and Tracy become closer. Meanwhile, Kenny tells Valerie to keep distant from him while he is proceeding with the divorce from his wife. But when Valerie accidentally finds out that Kenny does not plan on leaving his wife, ever, out of respect for their six-year-old son, she later tells Kenny some unsettling news about her.

Steve declares war by trying to find a date for himself just to make Clare jealous when she starts dating another guy, named Dick Harris, whom he can't stand. Meanwhile, Donna's new fireman boyfriend, Cliff Yeager, who saved her life during the brushfire, assists her at her sorority's Halloween Haunted House bash. At the reopening of the Peach Pit After Dark, Kenny does not attend, prompting Valerie to resort to her devious tricks again by asking for $100,000 so she can keep away from him. Also, Brandon tries to get closer to Tracy while Kelly hits on Mark.

David's gets a huge windfall when he inherits $250,000 after his grandfather dies. But it causes a rift with his father Mel over how to use it when David lets the thought of wealth go to his head. Kelly extends an olive branch to Valerie after learning from Steve over her condition, but Valerie must keep the fact that she really isn't pregnant under wraps at any cost. Meanwhile, Steve rashly challenges Dick to a crew race, much to Clare's anger. Tracy makes an overture to Brandon to appear with her on a presidential debate. Also, Cliff takes Donna on a camping trip where he tells her of his future plans, not involving her.

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.

The increasingly manic-mannered David takes Valerie, Steve and Clare for a wild weekend to Las Vegas where his increased drinking and gambling threaten to turn the events bad, and Ray Pruit is performing at their hotel. David ends up picking up two prostitutes and takes them to a seedy motel where they drug and rob him. David is forced to call Donna for help who arrives in Vegas to comfort him. She yells at Steve, Clare, and Valerie for letting David get out of control. Meanwhile, Kelly finally asks Mark to spend the night with her. Also, Brandon befriends Melanie, a diminutive young woman passing through town and who gives him advice on his future career.

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.

Steve pleads guilty to plagiarizing and avoids a hearing in front of Chancelor Arnold and the conduct council, but the corrupt and vindictive Professor Randall pursues a case against an innocent Brandon. At the last moment, Steve, with Clare's help, proves Brandon's innocence when they expose Randall for fabricating evidence against Brandon. Meanwhile, David hedges on investing in Valerie's club while Donna clashes with her uptight mother, Felice, over wanting to renew her relationship with David as part of her effort to help his mental recovery. Also, Kelly throws a surprise birthday party for Mark who becomes increasingly jealous about her and Brandon.

Valerie is surprised when Tom Miller, another old high school friend from Buffalo, comes for a visit and asks for a job at the After Dark club. Meanwhile, Brandon and Mark learn that they've applied for the same prestigious scholarship, which turns into a competition for both of them. On a job interview, Steve is hit on by the employer, Diane, and hesitates about what to do. Donna proves to be a lifesaver when she fills in as the receptionist at her father's office for the day. At the end, Mark shows off his true angry and arrogant colors to Kelly after losing the scholarship to Brandon, resulting in her breaking up with him.