The gang find themselves in trouble when an obnoxious teacher bans them from the class field trip unless they pass a test. On the day of the test the teacher does not show, so Mr. Belding's brother, Rod, takes over and offers to take the class on a special field trip. He happens to sweet-talk the kids, tells them what a free-spirited life he lives. He even just gives them an "A" just so there will be a field trip. He acts as their friend and it makes him very popular with the kids. However when Zack accuses Mr. Belding of harboring jealousy towards his brother, he later regrets it when he sees Rod for who he really is.
The students are in a panic over an upcoming history test. Even worse, the teacher, Mr. Dickerson, clearly relishes the idea of them all failing.
During several students are called to Mr. Belding's office to discuss the upcoming trip. They try to come up with a destination, but no one can agree, so Mr. Belding says that he will decide and let everyone know when he does.
Later, the gang studies for the test, knowing that if they fail there will be no trip. Unfortunately, thoughts of the sadistic Mr. Dickerson plague them even as they try to study. The day of the test finally comes, and to everyone's surprise Mr. Dickerson doesn't show up. Instead, Mr. Belding announces that Mr. Dickerson has basically had a breakdown, failing all of the other teachers and threatening them with detention. After hearing them complain, Mr. Belding has decided he needed some rest and fires him immediately. In his place is a substitute teacher: Mr. Belding's own brother, Rod. Rod has the students tear up their history tests and allows them to choose their own grades. Everyone thinks he's a great teacher because of it. Mr. Belding comes into and announces that the trip will be at Yosemite National Park, and everyone is very excited by the decision, although Rod makes some disparaging remarks about his brother not being much of an outdoorsman.
Later, Rod, Zack, and Screech hang out in Mr. Belding's office. Rod puts it in their heads that they'd have a better time white water rafting, and that he'd be happy to take them. Zack brings the idea to the others, and they all agree. Then they tell Mr. Belding that they'd rather go white water rafting with Rod than to Yosemite with him. Mr. Belding is obviously disappointed, but he agrees.
Rod decides to use some time to prepare the students for the upcoming trip. Mr. Belding sees this and insists that Rod bring his students back to the room at once. Zack is angry for his actions and accuses Mr Belding of being jealous of his own brother.
At last, it's time for everyone to leave for the class trip. However, Rod is nowhere to be found. Zack goes looking for him and overhears Mr. Belding and Rod in his office arguing. It turns out that Rod has decided to spend the weekend with a stewardess named Inga who is only in town for a few nights and wants his brother to just come up with an excuse for him. Mr. Belding refuses and throws him out. Before he leaves, Richard reveals his disappointment in Rod with the belief he hoped he'd become a better person and instead is still the same Rod who makes promises and breaks them. Rod leaves, but Zack turns away so he can't see him. After watching him leave, Zack regrets his earlier words to Mr. Belding.
Still Zack doesn't know how he can face his friends after seeing Rod for the selfish person he is. Returning to his class, Slater and Kelly are concerned for him. Zack tells them that he doesn't want to talk about it, apparently disappointed in Rod. Mr. Belding then announces to the class that Rod couldn't be there. Everyone's disappointed, but he convinces them that he'd still like to take them on the trip and everyone's happy again.
As the rest of the class is prepared to leave, they thank Mr. Belding for not cancelling the trip and Zack asks for a few minutes alone with him. After the rest of the students head to the bus, he questioned Mr. Belding's reasons behind covering for Rod and not telling the class the truth about his plans to go on a date with the stewardess. Zack admits he overheard his conversation between the two when he came to the office to look for Rod and having to see him for the selfish jerk he is. Mr. Belding understands how angry he is with Rod and apologizes for having to overhear their fighting. He knew how much the trip meant so much for Zack, his friends and their classmates. Therefore, Mr. Belding didn't have the heart to tell them the truth about Rod. In turn, Zack apologizes for his behavior upon realizing that Mr. Belding cared about his classmates. He forgives Zack, admitting that he wished he was a bit more laidback like Rod. Zack disagrees, admitting that the school has him, their principal as the better Belding.
- Mark-Paul Gosselaar as Zack Morris
- Mario Lopez as A.C. Slater
- Dustin Diamond as Screech Powers
- Lark Voorhies as Lisa Turtle
- Elizabeth Berkley as Jessie Spano
- Tiffani Thiessen as Kelly Kapowski
- Dennis Haskins as Richard Belding
- Edward Blatchford as Rod Belding
- Raf Mauro as Mr. Dickerson
- Dan Eisenstein as Nerd
- [Mr. Belding in his office annoyed with his brother for his selfish actions]
- Mr. Belding: I cannot believe you're doing this! The class trip leaves in five minutes, these kids are depending on you!
- Rod: Come on Richie, they'll get over it.
- Mr. Belding: They look up to you. What is so important that you would disappoint thirty kids?
- Rod: Richie, if you met this stewardess you'd know.
- Mr. Belding: You doing this to spend time with some stewardess?
- Rod: It's not just some stewardess. This is Inga and she's only in town for the weekend.
- Mr. Belding: See I knew, I knew it was a mistake to let you come to my school. You promised me you had changed. But no, you are the same Rod. You get people's hopes up and then you let him down.
- Rod: Richie, she's gorgeous, you should see her she's a 10! [a reference to Bo Derek's role as Jenny in the 1979 film]
- Mr. Belding: It's that what you're gonna tell the kids. That you dumped them for some weekend fling?
- Rod: Of course not. Tell them I'm sick, tell them anything, cover for me.
- Mr. Belding: I'm tired of covering for you!
- Rod: Come on Richie, don't be mad, we're brothers.
- Mr. Belding: [pointing to his office door] Get out of my school Rod!
- [After Zack talks to Mr. Belding alone.]
- Zack: Mr. Belding, why didn't you tell them the truth?
- Mr. Belding: What do you mean?
- Zack: About the stewardess. I heard everything.
- Mr. Belding: Oh you did.
- Zack: Everything.
- Mr. Belding: Well I'm sorry you had to hear that! I know how much Rod meant to you and just didn't want to ruin that.
- Zack: Sir, I acted like a jerk, I'm sorry for the things I said to you.
- Mr. Belding: I understand that Zack. Rod always was the more exciting Belding.
- Zack: Maybe, but we've got the better Belding!