Kelly's father Bill Taylor, arrives in town apparently to stay, while at the same time, she again catches Colin sniffing cocaine. Joe makes a professional call on Donna's cardiologist father who discovers that Joe may have a certain heart disorder. Meanwhile, Nat refuses to participate in Steve's film festival honoring Roger Corman after the gang sees him in one of Corman's movies from 1972 titled 'Unholy Rollers'. Things take a turn when Joan Diamond, a former actress and Nat's old fiancée, arrives for the festival. Also, Brandon continues to be jealous of Susan's ex-boyfriend Jonathan when he phones to speak to her and Brandon doesn't leave a message for Susan.

With Colin in jail, Valerie tries to arrange bail for him. Kelly finally gets out of rehab and moves back into the beach front apartment, and Tara briefly runs away from the rehab center to visit her. Meanwhile, Brandon and Susan, Steve and Clare try to rekindle the romance between Nat and his lost love, Joan Diamond, by taking them out on a triple date. Also, Joe's news of the success of his heart surgery finally relieves Donna.

Carl hosts Steve's weekend long 21st birthday bash on the ship Queen Mary in Long Beach, where the music group "The Goo Goo Dolls" entertains. Carl then asks Steve a favor: to have a chance with Clare who he has had a crush on. David and Donna grow more intimate while their producer Erik, makes a move on Donna and other women as well. Andrea Zuckerman arrives in town to have fun at Steve's party, and Nat brings Joan along who keeps feeling unwell. Meanwhile, Valerie hires an FBI agent, named Richard Ballen, to find Colin who's in the area trying to get access on a ship to take him to South America. Also, Susan tells Brandon that she has decided to leave town to accept a job offer at a newspaper company in Washington D.C. which makes him wonder if he has a future with Susan after all.

On the Queen Mary, Steve tells Clare about Carl's feelings for her and tries to persuade her not to fulfill Carl's wish. Meanwhile, David and Donna decide to get back together, while still avoiding Erik. Joan tells Nat that she may be pregnant from her constant sickness. While Colin is trying to get the necessary papers and identity to leave the country on a freighter, Steve and Brandon end up in jail from a barroom brawl after taking out their frustrations on drunken bar slobs in which Kelly and Valerie have to bail them out. Eventually, Nat proposes marriage to Joan who accepts. Colin is finally caught, Steve and Clare get back together, and Brandon coldly breaks up with Susan after she admits her career means more to her than anything.

Brandon is on a road trip through the USA when his car breaks down in a small town in Texas, and he encounters racism from the redneck locals after he befriends a young black girl, named Mariah. In Beverly Hills, Valerie seeks financial help from Kenny Bannerman, one of Jim Walsh's former coworkers, to revamp business for the Peach Pit After Dark. Meanwhile, David and Donna work together on another music video project and find that their renewed relationship may be on a short fuse. Also, Clare and Steve attempt to meet with each other after spending their summer away, unaware that they are at the same airport at LAX waiting for the other.

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.

Valerie and Kelly are reluctantly paired in a Christmas gift exchange, where Valerie goes shopping with Tracy to find the certain gift. Kelly gets a big surprise when she meets Joy, a half-sister from her father that she never knew existed. Meanwhile, Steve and Clare find themselves playing holiday matchmakers to his mother and her father during a Christmas faculty party. Also, David tries to get on the good side of Donna's conservative and domineering mother, Felice, who offends everyone again. Elsewhere, Brandon and Tracy share their exchange of gifts.

With a few hours before Brandon and Kelly's wedding, they continue to feel uncertain about the path they are on. Jim and Cindy Walsh arrive in town from Hong Kong to help plan Brandon and Kelly's wedding. Meanwhile, Valerie finally decides to get an AIDS test after Johnny confesses to her that he happens to be HIV-positive, and she asks David to come along with her for emotional support. Steve becomes dateless for the wedding when Sarah decides to go back to her husband after witnessing her friend's messy break up. After the caterer, Jacob, saves Donna's life, Donna agrees to go on a pretend date with him to make his ex-girlfriend jealous. This makes Noah jealous.