The plot follows five students at fictional Shermer High School in the fictitious setting of Shermer, Illinois, as they report for Saturday detention on March 24, 1984. Complete strangers, the five teenagers are all from a different clique or social group.
The students pass the hours in a variety of ways: they dance, harass each other, tell stories, fight, smoke marijuana, and speak on a variety of subjects. Gradually they open up to each other and reveal their inner secrets. They also discover that they all have strained relationships with their parents and are afraid of making the same mistakes as the adults around them.
However, despite these developing friendships, the students are afraid that once the detention is over, they will return to their very different cliques and never speak to each other again.