Mature teens will appreciate this story, written by its appealing two stars, of a brilliant young man with a troubled past. Will (Matt Damon), who grew up as an abused foster child in tough South Boston, works as a janitor at MIT. When he solves math problems that stumped the students, a professor searches for him, only to find that he is in jail for hitting a policeman. The professor promises that he will work with Will and will get him some psychiatric help.

When Will manages to scare off a string of therapists, the math professor seeks out his estranged friend from college, Sean (Robin Williams). Like Will, the survivor of a tough Southie upbringing, and, like Will, still struggling with his own loss, Sean is able to help Will realize that he is not betraying his friends by using his gifts to enlarge his world. Will falls in love with Harvard pre-med student Skylar (Minnie Driver). She and Sean teach him that the walls he built to protect himself from pain are no longer needed, and are getting in his way. NOTE: Very strong all-but-incessant profanity and sexual references.