Arnold, saddened by the rejection he keeps receiving from the opposite sex, gets advice and comfort from Julie before quickly falling in love with her.
With Barbarino now an orderly at a hospital, the Sweathogs try to get jobs there, too. Meanwhile, Kotter tries to get the gang to return to school.
Freddie and Juan plan to do an act together for the upcoming talent contest, while Carvelli has some bribed judges up his sleeves. Arnold and Beau take over as judges, leaving Murray in the third spot.
Horshack saves a lonely, overlooked girl named Mary Johnson from committing suicide by jumping off the ledge of the school.
Juan asks Vinnie to marry his cousin, who needs to get a husband to stay in the country Vinnie reluctantly agrees but when the other Sweathogs find out, he gets mad. Eventually, the girl ditches Vinnie for the marimba player at the wedding.
When Mr. Woodman comes to Vinnie's hospital for an operation, Vinnie loses him and he and the other Sweathogs try to find him.
After Horshack refuses to dissect a frog in class, his grade is in jeopardy.
To get up his nerve with Mary, Carvelli offers Arnold liquor. He doesn't like the idea at first, but as time goes on, he becomes addicted to drinking; developing a scary and unlikable new personality that only turns Mary away.
Beau, a new student in the remedial class, seems to be taking all the attention away from the Sweathogs.
The Sweathogs remember how they tried to buy a used car from Vinnie's uncle.
Arnold's relationship with Mary gets serious. Then he finds out he has to move and leave the school. Upset, Arnold decides to propose marriage to Mary. She accepts.
Vinnie is forced to deliver a baby in an elevator.
Vinnie buys himself a new coat for Christmas, but when he shows it off at school it gets dirty, then stolen when he takes it to get cleaned. His day gets worse when Woodman buys himself a similar coat and the thieves he claims are big guys turn out to be two punk kids.moreless
Vinnie gets a new apartment, but when the Sweathogs decide to use it, Vinnie asks them to leave.
Vinnie becomes depressed when it seems that he has lost his way with women.
Convinced that the school newspaper is too dull, Juan sets out to turn it into a tabloid, bringing down his friends' names in the process.
The Sweathogs opt to change Mr. Woodman's tired old school song. A hot music artist wants to record it but Woodman refuses until he sees how much money he could make. However, the song turns out to be not original.
The gang is liable to get in trouble when the X-rated film Carvelli brought into school is accidentally mixed up with a film on sexual education.
Mr. Woodman's niece Kelly is babysitting for the Kotters when Juan drops by the apartment. The two abruptly fall in love and decide to move in together, but the romance begins to crumble when it seems that they can't respect one another's interests.
A younger student begins to imitate Freddie, not much to Freddie's liking.
Gabe announces that he is now the vice-principal and Mr. Woodman is the principal. The Sweathogs are pleased, until Gabe gets strict. After Vinnie visits the school to tell the gang he's dropped out, the other Sweathogs decide to follow in his footsteps.
A practical joke backfires when the new Sweathog, Beauregard De Labarre sets Epstein up for a date with a "married woman."