Sam (Rory Culkin) is a shy and sensitive teenager whose curiosity is always getting him in trouble. When he bends over to look at a video camera, its owner, George (Josh Peck), viciously attacks him. And this is not the first time that this school bully has assaulted Sam. His girlfriend Millie (Carly Schroeder) is upset that the teachers ignore the problem and try feebly to deal with his unruly behavior by giving him detentions. When Sam tells his older brother, Rocky (Trevor Morgan), they agree that something should be done to put George in his place — but they don't know what. Rocky's best friend Marty (Scott Mechlowicz) is a hellion who smokes marijuana and drinks a lot. His father committed suicide and neither he nor his older brother has come to terms with the shock. Marty also seems to derive pleasure out of taunting their other friend Clyde (Ryan Kelley), who is being raised by two homosexuals, by constantly questioning his ability to be tough.

When Rocky tells Marty about the latest beating that his brother has received from George, they come up with a revenge scheme that involves inviting the despised youth to a fake birthday party for Sam. They intend to rent a boat, take him out on the river, make him strip, and then toss him in the water, forcing him to get home while naked. At first, Sam is against the idea, saying "if we hurt him, we'll be just as bad as him." It so happens that his first date with Millie is on the day of the planned revenge, so Sam doesn’t tell her about the prank.

George, usually an outsider, accepts the invitation. At home, he has begun a video diary, taking pictures of his room, his mother on her exercise machine, and the street where he lives. He joyfully enters the car when Marty and gang arrive to pick him up. George has a birthday present for Sam and tries to fit in with the group. He tells them about his learning disability and the strange way he sees the world.

Millie is angry when Sam lets her in on the scheme as they are heading for the boat. She wants him to convince his brother to call the whole thing off. But once they're all in the boat, Marty takes charge of the festivities and suggests that they play a game of truth or dare. Most of the challenges have to do with proving one's manhood or revealing intimate feelings about sexuality. The tension escalates when Marty lets George in on the real reason why he is there. The bully explodes in anger and starts verbally attacking each person on the boat. Everyone is caught up in the violence and the anger of the moment.

First-time writer and director Jacob Aaron Estes has crafted an intense and riveting morality play that vividly conveys the anger and violence that stem from the machismo posturing of boys and the hatred that enables people to write others off and treat them with disdain. The parents of the characters in this small Oregon town are not seen until the end of the film, and so the entire focus is on the sibling relationship between Sam and his older brother, and on Rocky's rift with his two best friends once he decides they must put a stop to the revenge plan.

The screenplay won Estes the Nicholl Fellowship in Screenwriting, and at the 2004 Sundance Festival, the Humanitas Award. These accolades are well deserved. The screenplay accurately conveys the pain brought upon others by bullies and, even more importantly, the story opens up the lonely and tormented life of George in a sympathetic way. Estes deserves further praise for the rich ethical dimensions of the closing scenes of Mean Creek. There are so many less edifying paths he could have taken.