High-school student Zach Harper sets out to complete the "Dirty Deeds", an outrageous list of ten challenges that must be completed between dusk and dawn on the Friday night of his high school's homecoming weekend. The only student to complete the entire list, Duncan Rime, did so in 1989 when only 8 tasks comprised the list. Rime later reveals that whenever someone completes the entire list, more are added to it.
Zach attempts to complete the deeds for a classmate, the beautiful Meg Cummings. Meg's younger brother, Kyle, wants to do the challenge to earn the respect of the school's jocks, who are constantly bullying him. Meg is concerned for her brother, and she insists that Zach stop him from trying to do something so foolish. While Meg had no intention of Zach attempting the deeds in place of her brother, Zach decides to take on the challenge.
The night begins, and Zach easily checks off the first item on the list—drink beer in front of the cops—by pouring a beer into a coffee cup and consuming it in front of them. This way, the cops, who are determined to stop all those who attempt the deeds, have no idea of Zach's intentions of completing the list. As Zach attempts the nine remaining deeds, the jocks do everything in their power to prevent him from completing it. Throughout his crazy night, Zach enlists the help of those around him to accomplish the difficult tasks. Along the way, Zach meets Duncan Rime who tries to warn him about how hollow the victory can be. Afterwards, Zach refuses to continue, but Dan and JD (the tough kid from Deed #2) decide to try to ruin the carnival so that Zach will be blamed. With some last-minute help from Vincent Scarno (the owner of the car from Deed #8), Zach is able to turn the tables in time. In the midst of everything, Zach and Meg end up falling in love over the list of "Dirty Deeds".
