Season 4

The gang begin their senior year, but rather than it being a positive time, things turn sour when Zack and Slater clash over the new girl at school.

It's student-teacher week. Mr. Belding and Zack switch places. Kelly is Slater's History teacher, but Slater thinks she's being too serious about it. When she gives the class a test and everyone skips out on it, Zack faces a hard decision: to be their friend or their leader.

During a project for TV ads, Screech comes up with a new flavor of sauce, but the gang might go out of business when Screech becomes the target of a snobbish girl.

Transfer student Tori is introduced in this episode, but Zack and Tori don't hit it off, and they are paired up for an ad project. Lisa alienates the Dance Committee before the Fall Ball.

When Lisa receives word that a recruiter from FIT wants to interview her, the gang help her put on a fashion show at The Max. However, the close working conditions mean Zack and Lisa grow close, leaving Screech brokenhearted and bitter.

Zack participates in a Bayside's teen hot-line, and becomes close to a disabled girl. Meanwhile, Screech takes on a rambunctious boy.

As the annual masquerade ball approaches, Zack and Slater make a bet about who can kiss Tori first. However, when she discovers their scheme, she decides to get revenge, while Screech's love letters to Lisa cause all manner of mix ups.

If Zack can just get out of detention with Mr. Belding, he can win a trip to Hawaii. Instead the whole gang ends up in detention with him, trying to get him out.

A.C. and his father fight over where he should attend college and Zack tries to fix it. Jessie becomes a cheerleader and worries about college acceptances.

The gang learn about the dangers of drinking and driving when, after getting drunk at a party, they get into an accident in Lisa's mother's car and try to cover it up.

Slater is horrified when his girlfriend from Germany arrives at Bayside as a new student. Zack helps hide the relationship from Jessie, but it is only a matter of time before she finds out, and Slater must figure out where his heart lies.

Zack appears to have negotiated a great deal on class rings for the senior class, but it turns out he has been scammed. While he plots revenge, a misguided bet between Tori and Lisa leads to Screech falling for Tori.

On Valentine's Day, the gang reminisce and share memories of love and past romance.

A member of Bayside's alumni dies, leaving $10,000 to the students. It is suggested that school sports should receive the money, but deciding which sports are most deserving leads to a battle of the sexes, and some cheating on Zack's part.

To go on a ski trip, the gang conjures up a teacher's strike only to learn that it could affect the academic bowl.

Slater is pleased when his younger sister J.B. arrives at Bayside, but his happiness is short lived, as she wants to date Zack, and Slater does not approve.

As the senior prom approaches, Zack discovers he still has feelings for Kelly. However, she already has a date, and Zack resorts to skulduggery to win her hand, while romance brews elsewhere.

The gang decide to make a video version of the annual yearbook, but Zack has other ideas and decides to use it to sell a dating video made from the video clips. However, he regrets his decision after Screech mistakenly puts Kelly on the video and she starts getting calls from other guys.

When his friends forget his birthday, they try to throw him a late surprise party. Screech, upset that his friends didn't remember, takes advantage of his new hall monitor position and makes it difficult for them to plan it.

The gang put on a rap version of "Snow White and the Seven Dwarfs". However, when Jessie and Zack find out they have to kiss in the last scene they start to doubt their friendship and question their feelings for each other, falling out with Kelly and Slater in the process.

To avoid a Physics test, the gang throws a baby shower for Mr. Belding's wife Becky. As they are leaving the school, an earthquake strikes, trapping Zack and Tori in the elevator with Becky, who goes into labor.

Zack, Slater, Screech and Lisa reminisce about their summer working at Malibu Sands beach club and attending Jessie's father's wedding in Palm Desert.

Screech is left to look after Slater's chameleon when he goes away, but things go awry.

The senior class want to leave a gift to Bayside's future students and suggest a contest to come up with a new school song. However, Zack decides to rig the competition in his favor in order to be remembered for more than just his bad behavior.

In 2003, the senior class find a video time capsule buried by the gang in 1993 before graduation, and Mr. Belding, still Bayside's principal, watches it with them.

As graduation approaches, Zack learns that he is just one credit short of graduating. Desperate to get extra credit, he joins Bayside's ballet company, and when illness strikes some of the other cast members, he calls on the gang for help.