The last day of school contains many problems for both teachers and students of Riverton High School in Washington state, and there are multiple storylines about this.
The principal, Harold Lewis, must discipline English teacher William Pratt, who has let his professional frustrations get the better of him, while guidance counselor Vanessa Jones attempts to get through to student drug dealer Wex Presley, who is ruining her students.
Principal Lewis' daughter, Karen, is having trouble with her boyfriend, Tommy who doubts a future with her.
Dara McDermott is a outcast who craves drugs and one of Wex's clients.
A pregnant girl named Robin Walters argues with her boyfriend, Kevin Rhodes, about her future options
The local bully Ricky Herman begins to recognize the consequences of his actions over a date rape.
Unbeknownst to these people, two outcast bullied students, Daniel Lynn and Barry Shultz, are about to shoot up the school as an act of revenge against their tormentors. Barry, however, is having second thoughts, while the seething Daniel prepares to unleash his rage. Daniel decides to attack his high school on the last day, insisting that he does not care if he lives or dies, tired of constant harshness and abuse from his uncaring father, Artie, and from bullies at school.... Ricky among them.
On the last day, Daniel carries out his plan, aided by Dara, who spontaneously joins him. Daniel confronts three of his past tormentors: Paul, Ricky, and Jeff, and kills them in cold blood. Kevin is shot and killed when he and Robin come into the line of fire, much to Daniel's regret, while Robin is spared.
Meanwhile, Dara walks into her English class and kills Mr. Pratt, and Karen, who had been a rival for the attentions of Tommy. Dara is then subdued by bully Donny Pritzee, and she is turned over to the police. Barry walks away from the school, having bailed out on the plan, believing there are other responses to the abuse he and Daniel suffered in the past. A lone gunshot then rings out as Daniel commits suicide.
As the film ends, a reporter informs the public of the school shooting, revealing that Daniel committed suicide, and the camera turns away from the TV to show Barry's and Daniel's shocked parents watching. (Note: the reporter mentions the victims as innocent kids... completely not mentioning that they were troublemakers and bullies who were indirectly responsible for Daniel and Barry falling off the deep and encouraged them to plan this shooting spree in the first place.) At Daniel's home, the phone begins to ring, but Artie cannot bring himself to pick it up. The film then ends as a voice lists off major incidents of violence perpetrated by minors.