At the start of the show, bad-boy Dylan befriends squeaky-clean newcomer Brandon and dates Brandon's sister Brenda. Later, he cheats on Brenda as he begins dating her best friend Kelly. He witnesses his felonious father's death by car bomb and inherits $10 million from his father's estate.

After being carjacked at gunpoint, Dylan meets his 12-year-old half-sister Erica, who he never knew existed, and his father's mistress, who promptly scams him out of his inheritance.

Soon Dylan becomes addicted to heroin and gets into an accident while under the influence. After several days in a coma, he goes to rehab.

Fresh from rehab, Dylan receives a letter from a stranger stating that his sister Erica is in trouble. He hooks up with Jay J. "Jonesy" Jones, an alcoholic FBI-agent-turned-bounty-hunter-slash- private-investigator. Jonesy leads Dylan to Mexico to recover his fortune and rescue his long-lost half-sister from the evil mistress.

Some time after the sister/inheritance issue is resolved, Dylan goes undercover at a commune to rescue Kelly from a cult.

Later, while researching ideas for a screenplay he is writing with friend-from-rehab Charlie, Dylan goes to a hypnotist who helps him figure out that in a past life he was a gun-toting outlaw named Billy McCoy. He also learns that he was in love with Kelly (in the form of a rich, upper-class woman) as far back as the Wild West. The screenplay idea is ditched after Dylan learns that the financial backer for the film has ties to the mobster who killed his father.

Six months later, Dylan marries the daughter of the mobster who was believed to have killed his father. Later that night, his new wife is shot to death by her father's hitmen, who were aiming for Dylan. Unable to cope with this development, he leaves Beverly Hills for no particular destination, with no indication of whether he will ever return.

While Dylan is gone, Brandon and Kelly rescue Dylan's half-sister from her chosen career of teenage prostitution.

Dylan returns to Beverly Hills three years later and begins dating professional ice skater Gina. During this time, Dylan takes Kelly on a date to Mexico and smuggles heroin on the plane on the way back.

In full-blown addiction, Dylan finds out his dead wife's grave has been moved to an unknown location, so he buys a gun with the intention of killing her mobster father. Dylan is promptly arrested for illegal gun possession and (also illegal) heroin possession.

After Dylan, high on drugs, accidentally injures his good friend Donna by pushing her into a pool, his friends stage an intervention. Convinced he can quit cold-turkey, he refuses their help and lands himself in another coma.

Later, Kelly and Dylan, now clean and sober, make plans to again smuggle drugs from Mexico, this time for a schizophrenic friend whose doctor has refused to refill a prescription.

Also, a stranger saves Dylan's life after a jet-ski accident, half-sister Erica visits with her white-supremacist boyfriend, and Kelly is hypnotized on stage at a magic show in front of Dylan, Gina, and Kelly's boyfriend Matt, and she reveals that Dylan is the one she would want to be with if stranded on a desert island, upsetting Gina and Matt and reminding Kelly and Dylan that they are soulmates.

Afterward, Gina narrowly escapes an attack by a knife-wielding serial rapist.

In the final season of Beverly Hills, 90210, Dylan is clean and sober, but nonetheless he is arrested for drug possession again when he is found in a limo with someone else's coke.

Shortly after Dylan escapes death at the hands of the brother of the owner of the cocaine, he sees his previously blown-up father walking away from a plane crash on the news. Dylan discovers that his father has a wife and son and is living under the Witness Protection Program in Arizona. They decide that leaving the Protection Program is too dangerous, and they go their separate ways.

Later, Kelly mistakenly thinks that Dylan has died in a surfing accident, and she realizes that she still loves him, and she calls off her engagement to Matt. It's just as well, it turns out, because Matt's brother has just been killed, and he has decided to move to New York to help raise his nephew.

Dylan and Kelly get back together and live happily ever after, apparently.

Yeah, right.