Harrison (Charles Grodin), Penny (Alfre Woodard), Julia (Kyra Sedgwick) and Milo (Tom Sizemore) die in 1959 when the bus they are riding crashes. The four continue as ghosts, guardians to the child born at the moment of their deaths. Baby Thomas grows up to be a businessman (Robert Downey Jr.) who has memories of his playmates, but assumes they are products of his youthful imagination. When the ghosts realize they need Thomas' help to move on, they decide to make an appearance once more.