Andy plots a major prank: to "pants" everyone during a school assembly using a special belt latch.
It begins at the gym. Andy dressed as a superhero says that his sister Jen is going to do a stunt called a Triple Pyramid, but he's thinking of doing a Quadruple Pyramid to impress Lori Mackney. The girls make the pyramid, and Andy jumps off a pyramid provided by Danny. He ends up landing in the hoop. Jen calls Andy a freak, and Craig accuses him of making him miss and threatens to "kick his butt". Lori says "when are you gonna grow up?", and Craig tries to make a swing at Andy. Andy ends up in his underpants.
Back at Andy's house, Andy says to Danny that even though he thinks his plans through, he seems to tend to end up in his underwear. Danny says that everyone has an off day, but Andy says that if ending up pantsed is an off day, he's had plenty, and bets the whole school has seen him without his jeans. Andy decides to get revenge (revenge on who?)
At the table, Jen is complaining about Andy's antics and Andy is imagining her as a duck. Freda tells him to listen, and Jen says that she asked DeRosa to organise an all-school pep rally the next day with a whole-body photo and an award for Best Student.
Andy tells Mush that it's a perfect spot for his "revenge" prank, but he can't think of a prank. Mush delivers a pizza for Mrs Weebles with smoke as a prank via a remote control latch on his belt.
That night, Danny gives Andy belts with latches that undo the belts. The next morning, Andy sells the belts, but Jen thinks they are dumb. However, Teri and Craig buy a belt apiece. This inspires several other students, including Lick and Leech, to want belts. (Lick and Leech intimidate their way into getting theirs free). Jen eventually buys one. Andy hides a timer in the cupboard, which will send a signal to unlatch everyone's belts at the time of the all-school photo. However, the boys find out Lori is wearing one of the belts, and Andy doesn't want to pants Lori. The janitor takes the timer. Andy walks up to Lori and they talk about the belt, which someone named Ellen or Alan gave to her. Lori is impressed that Andy is "trying to make amends". Andy tells Lori that her belt is "defective" and wants to give her another, but she doesn't want it. However, she does hint that she might like him.
Andy talks to Danny in the hallway about how he is glad that Lori hinted that she likes him, but worried because Lori is the only person he doesn't want to pants, and he really doesn't want to pants her. Danny notes that Lori can't wear the belt all the time.
Andy and Danny are in the gym, planning to sneak Lori's belt out of her locker. They look in the girls' lockers, but can't find the belt. However, a crowd of girls see Andy and Danny looking and are shocked. In the locker, Andy decides pranks are more important to him than whether or not Lori is pantsed.
Jen decides that Lori is the winner and decides to defuse his de-pantsing device. He asks a janitor, who gave it to Mr Hutchins, who gave it to Mrs Woomer, who doesn't have it. Mrs Weebles has it. She decides that he can have it back after school, but Andy dashes out, shouting "I'll be dead after school! I must save Lori's pants!". Mrs Weebles decides that "Lori's pants" is just "wacky teen lingo" for something else.
Andy runs down the hall, riding on a cart, (losing his pants in the process) and the photo is taken and everyone is pantsed. However, Andy does up Lori's belt before her underwear can be in the photo. Andy (who is in the basketball hoop with Danny) decides that despite not being perfect, the plan still worked very well as he pantsed everyone and saved Lori's pants.