The film was followed by the sequel Sometimes They Come Back... Again.
Jim Norman, a high school history teacher, moves back to his old hometown to teach after being offered a job there. He moved from the town after he witnessed his brother, Wayne, murdered by a group of thugs. The murderers themselves were killed shortly afterward by an oncoming train, having parked on the tracks.
He has recuring nightmares about his brother's murder as he starts teaching in the town. Students close to him start to be involved in various accidents that look like suicides. One student is run off a bridge by a Chevrolet Belair that only Jim sees. Another is found hanged in a barn after Jim has nightmares about her being hounded by a group of thugs. As these accidents continue, more students appear in his class who bear resemblances to the thugs who murdered his brother. As Jim becomes more involved in pursuing the thugs and finding their intentions, they kidnap one of his students, show him their "true" faces, burnt and fleshless from the train accident, and murder him in order to allow the last thug to take his place in Jim's classroom.
After confronting the new students, Jim discovers that their plan was to come back from the dead and "finish what they started;" murdering Jim in the same way they murdered Wayne in order to keep themselves out of Hell. They intend to have a child witness the event, leading them to try to kidnap Jim's son Scott. Jim finds out that there is a way to let his own brother come back. The gang also needs the remaining living member of their gang, Carl Mueller, who left before the train struck. Jim finds Carl, who panics, thinking Jim wants revenge. He runs back to town, fulfilling the gang's plan for a reunion.
The gang harasses Jim's family at their home to ensure Jim's compliance in reenacting the murder. After the gang releases the family, Jim hides them inside a church, which the demonic gang cannot enter. Jim tries to bring his brother back in the church's graveyard as the gang lures his wife and son outside and hold them hostage. Jim finds that something is blocking Wayne's return, and must cooperate with the thugs in reenacting the murder. He returns to the train tunnel in which the first murder took place, though both he and Carl change their dialogue and actions from those taken 27 years before. Frustrated, the gang leader stabs Carl, which allows Wayne to come back. Wayne distracts the gang members while Jim gets his family out of the gang's car. As the family runs, the gang tries to escape in their car, only to have it stuck by a ghost train which sends them back to Hell.
Wayne offers to have Jim come with him to the afterlife, which Jim refuses because of his family, but tells Wayne says he can move on to heaven and see his parents because the greasers are no longer a threat. Wayne embraces Jim hoping to see him one day in afterlife and goes back to the afterlife as Jim's family heads home and Jim finally has found peace after all these years.