The new girl in Kotter's class declares that she is going to become a Sweathog, but the other Sweathogs strongly oppose her joining their group. So she pulls a stunt to prove her worth which backfires getting the Sweathogs nearly expelled.
The Sweathogs convince Gabe to audition at a local hot spot, never expecting him to succeed, but after Mr. Charnoff a slick agent gets through with him, it's goodbye teacher, hello show biz. First of a two-part episode.
Freddie is prescribed painkillers to treat a nagging injury he suffered playing basketball ... and soon becomes hooked. His friends become concerned about Freddie's increasingly scary behavior, but "Boom-Boom" tries to brush them off - after all, it's just "vitamins." What becomes even more scary is that Horshack blindly believes his friend's explanation, even though it becomes clear that Freddie needs help before something goes horribly wrong.
The Sweathogs sneak out to a strip club and recognize one of the dancers as their former classmate Hotsy Totsy. Shortly after, the Sweathogs, Kotters, and Woodman step in and try to find her a more respectable job.
Carvelli goes to Buchannan High as part of an exchange program and tells the students about his encounter with aliens. Woodman, convinced his story is true, plans to go on the spaceship when it lands in the schoolyard.
Kotter becomes the new vice principal and the Sweathogs think they can get away with anything they want. When they tie up Carvelli and Murray, Kotter gives them detention and and they decide to quit school and get real jobs.
Barbarino gets his own apartment and the Sweathogs think they have a new hangout. Barbarino tells them they are only welcome at his apartment when he invites them over. Offended by this, the Sweathogs storm out of his apartment.
Carvelli offers to sell the Sweathogs his car so they tell him about the time they bought a car from Barbarino's uncle. While waiting at the hospital for the car, the Sweathogs see Uncle Louie wheeled in on a gurney after a car accident.
Buchanan High gets a new student, Beau DeLabarre from New Orleans, who uses his southern charm to hit on several girls including Juan's girlfriend. Juan strikes back, then Beau sets him up with a girl who has a jealous husband.
Carvelli brings in an X-rated film and asks Epstein to show it for the guys. Meanwhile, Julie prepares to show a sex education film to protesting parents. The two films get mixed up and the parents see the X-rated film.
The students are told as part of their biology requirement they're going to have to dissect a frog. And Arnold refuses to do it. He even protests by trying to take the frogs. He is told if he doesn't do it, he will get a failing grade and he's asking the other Sweathogs for support.
Freddie rewrites Woodman's version of the school anthem. A big-time recording artist hears him singing it and decides he wants to use it on his next album. But Woodman opposes the idea of the school song going commercial.
Vinnie selfishly buys himself a new camel-hair coat for Christmas. He feels it makes him stylish. So to him it's a tragedy when a couple of hoods steal it from him. Will the coat crooks be caught or a Christmas lesson taught?