The plot follows five students at fictional Shermer High School in the widely used John Hughes setting of Shermer, Illinois (a fictitious suburb of Chicago based on Hughes' hometown of Northbrook, Illinois, Shermer is a street in Northbrook, and the school in Northbrook, Glenbrook North High School is on Shermer), as they report for Saturday detention on March 24, 1984. Complete strangers, the five teenagers are all from a different clique or social group.