Zhang Zhen (nickname Si’r) is a student in junior high in Taipei in 1959. After failing a test, he is forced to attend night school. This upsets his father, a career government worker, who is aware of the delinquency rampant among night school students and worries that it will affect Si’r. The next morning, Si’r and his father listen to a radio broadcast listing students accepted into various schools in Taipei. A Brighter Summer Day 1991
A year later, Si’r, along with his best friend, Cat, spy on the filming of a period drama in a movie studio. Caught by a guard in the rafters, they steal his flashlight and flee the studio, returning to their school. Si’r, noticing movement in a darkened classroom, turns on the flashlight and startles a pair of lovers, whose identities remain unclear. Two gangs of students, the Little Park Boys and their rivals the 217s, are introduced. Si’r is not a member of either gang, although he is closer to the Little Park Boys. The Little Park Boys are led by Honey, who is hiding in Tainan from police after killing one of the 217s over his girlfriend, Ming. Sly leads the gang in his absence. Sly and Si’r become rivals after Si’r gets Sly in trouble, believing him and his girlfriend, Jade, to be the pair of lovers he saw. Meanwhile, Si’r and Ming meet by chance and become friends.
Sly proposes a truce between them and the 217s, arranging Western pop music concert with members from both gangs. Preparations for the concert appear to be going well until Honey, wearing the stolen uniform of a sailor as a disguise, unexpectedly resurfaces and berates Sly for setting up the concert; however, he realizes the gang respects Sly more. The night before the concert, Honey meets with Si’r, who he has taken a liking to, and “bequeaths” Ming to him, believing him to be a stable boyfriend. The following night, Honey appears outside of the concert hall, antagonizing the 217s. Narrowly avoiding a beating, Honey takes an apparently friendly walk with the 217’s leader, Shandong, only to be murdered when Shandong pushes him in front of an oncoming car.