- Directors: Clint Eastwood
- Producers: Clint Eastwood, Robert Lorenz, Judie G Hoyt
- Writers: Novel, Dennis Lehane, Screenplay, Brian Helgeland
- Genres: Crime, Drama, Mystery, Thriller
- Actors: Sean Penn, Tim Robbins, Kevin Bacon, Laurence Fishburne, Marcia Gay Harden, Laura Linney
The film opens with three boys, Sean Devine, Jimmy Markum, and Dave Boyle, playing hockey in the street. While playing, the boys find a section of sidewalk concrete that is still drying. Jimmy impulsively writes his name in the cement and Sean follows. Dave begins to write his name in the cement, but a car pulls up and a man who pretends to be a plainclothes police officer gets out, scolds the three boys, and tells Dave to get in the car. After a second man in the front passenger seat (who appears to be a priest) turns and smiles at the boy, Dave looks out the back window to see Jimmy and Sean staring back at him as the car moves away. Hearing that Dave was taken away by a police officer, the parents of Jimmy and Sean agree that something is wrong and begin to look for him.
The film then cuts to Dave in the basement of the two child molesters who took him and then to Dave running away from the house through a forest.
Twenty-five years later, the boys are now grown and still living in Boston. Jimmy (Sean Penn) is an ex-con running a neighborhood store, while Dave (Tim Robbins) is a blue-collar worker, still haunted by his abduction. The two men are still neighbors and related by marriage. Jimmy’s 19 year old daughter Katie (Emmy Rossum) is secretly dating Brendan Harris (Thomas Guiry), a boy Jimmy despises. She and Brendan are planning on eloping to marry in Las Vegas.
The film ends with the camera zooming towards Mystic River and fades to black.