Zack is happy to attend his Ethics class, because the teacher is very easy and he knows it'll be easy to get a good grade with little work. Then he finds out that their regular teacher has won the lottery and retired, and now they're getting Professor Hemmings, who is an extremely demanding teacher. He attempts to talk to the class about ethics, but they don't seem willing or able to do it, so he warns them that each semester a half of the students fail and need to repeat the course.
Zack, Slater, Leslie, and Alex all commiserate about the incredible work load of this class, and Slater, who works at the Student Union, knows that he won't be able to keep up with his schoolwork and also with his job, so he decides he needs a substitute. He has to settle for Screech, who quickly proves himself to be a bust in the food service business. He manages to get Kelly and Mike Rogers to help him out, though, and with their help he even manages to get a promotion to assistant manager.
Meanwhile, the ethics class is taking its toll on all of the students, and panic sets in as the midterm exam looms near. Zack attempts to sweet-talk Professor Hemmings, but it doesn't work. As Professor Hemmings leaves the classroom, he leaves behind a piece of paper which turns out to be a copy of the midterm. Later, both Zack and Slater manage to rationalize using the midterm, and after Alex learns about it she goes along as well. Leslie, however, wants nothing to do with it, and looking out for her friends' best interests, tears up the exam, throws it in the garbage can, and then takes it out to the dumpster.
Screech continues making a mess at the Student Union, driving both Kelly and Mike Rogers away with his "Fiesta Day" theme. The rest of the staff quickly follows, and Screech finishes it off by firing himself.
Later that night, Zack, Slater, and Alex all search through the dumpster, looking for the exam. They are surprised when Leslie also comes out looking for the exam, and she admits that, because of how much work Professor Hemmings has heaped on them, she's decided to cheat as well. After some searching they find both pieces of the exam.
The next morning Professor Hemmings comes in with the midterm exam, and to everyone's surprise, he throws it in the garbage. He then admits that he's strategically placed copies of the midterm all over campus, so that everyone in the class would have a chance to see it and decide if they're going to cheat or not. He gets Slater, Alex, and Leslie to all admit that they would have cheated, while Zack surprises everyone (including himself) by saying that even when he had the chance, he chose not to cheat. Professor Hemmings is happy, because he's finally gotten the students to think about and be able to discuss ethics, so Zack accuses him of being unethical himself by tricking everyone. This pleases Professor Hemmings even more, and it leads into the discussion of ethics he's wanted all along.