Plot
Ben Mears attacks priest Donald Callahan in a homeless shelter in Detroit on Thanksgiving. As they corner each other in Callahan's upper storey office, a struggle ensues and they both fall out a window onto the street below. In the hospital where he and Callahan are taken, Ben is asked by an orderly why, as a Christian himself, he shouldn't just let Ben die for attacking a priest. Ben then murmurs, "Jerusalem's Lot," and begins to tell his story.
Some time earlier, Ben, then a successful writer, returns to his hometown of Jerusalem's Lot (also known as "'Salem's Lot" to the locals) in Maine, intending to write a new novel. He tells Susan Norton, a waitress and former art student, that when he was a child he accepted a dare to enter the house of Hubie Marsten, a Prohibition-era gangster. Local legend has it the Marsten House is possessed by evil, and that Marsten was a devil worshipper who murdered children. Ben overheard Marsten begging for his life to some unseen evil force before seemingly hanging himself. Attempting to flee from the house, Ben believes he heard Marsten's last victim crying for help, but Ben was too afraid to find or help him. Paralysed with fear, Ben remained stranded inside the house until his aunt found him the next morning. Now, nearly thirty years later, Ben plans to rent the house to bring catharsis to himself and gather material for his novel, but discovers it has been sold by Larry Crockett to antique dealers Richard Straker and Kurt Barlow.
Despite the picture perfect façade of the small town, Salem's Lot is rife with dark secrets: Crockett is an immoral businessman who sexually abuses his teenage daughter Ruth. When Ruth spends time with a disabled garbageman named Dud Rodgers, Crockett gets him fired. Eva Prunier, proprietor of the boarding house where Ben stays, played evil games with Marsten when she and her peers were teenagers. Charlie Rhodes, cruelty-obsessed Vietnam veteran and school bus driver, torments the children he transports. Trailer park residents Roy and Sandy McDougall physically abuse their baby, blackmailing Dr. Jimmy Cody after he has an affair with Sandy.
Following Straker and Barlow's arrival, local child Ralphie Glick is murdered and his body is never found. His brother Danny sickens and dies after being visited by Ralphie, who has become a vampire. Dud Rodgers meets Barlow who offers him a chance to be free of his physical disability. Dud accepts unquestioningly and Barlow turns him into a vampire. Laborer Mike Ryerson buries Danny after his funeral, then also sickens and dies. He returns from the grave as a vampire to tempt gay high school teacher Matt Burke, who repels him but suffers a heart attack. Ben's blossoming relationship with Susan causes jealousy with her old boyfriend Floyd Tibbits. Floyd is bitten by Dud and slowly becomes a vampire. After starting a fight with Ben, Floyd and Ben spend the night in jail, and Floyd uses his vampire powers to crawl through the ventilation shaft to taunt Ben. Ben refuses to allow him to enter his cell, and Floyd is found dead in his own cell the following morning, having chewed open his wrists in an attempt to drink his own blood.
Susan and schoolboy Mark Petrie are captured by Straker when they break into the Marsten house. Mark escapes, but Susan is taken to the cellar to meet Barlow. Ben, Mark, Callahan and Cody begin acting as vampire hunters. In the Marsten house, they find Straker's body hanging from the rafters, having been drained of blood. They begin destroying the sleeping vampires in the cellar, but Ben discovers Susan has been turned. Instead of destroying her, Ben intends to find and destroy Barlow, hopeful that Susan might be restored upon his destruction.
After Barlow kills Mark's mother, Callahan tries saving Mark by confronting Barlow, but finds his religious faith is not strong enough. Callahan is forced to drink Barlow's blood, corrupting Callahan and turning him into Barlow's servant. Larry sees Ruth join Dud in the night, and despite his wish to be with her, is consumed by the vampires. The town's ranking police officer, Sheriff Parkins Gillespie, discovers what is going on in Salem's Lot and decides to leave.
In the hospital, Burke is murdered by Callahan under Barlow's control. Ben, Jimmy and Mark realize Barlow is hiding at Eva's boarding house, but as they arrive there, Jimmy is killed by a booby trap. Ben and Mark destroy Barlow, but not before he taunts Ben, likening Ben to himself as another parasite who preys on the tragedies of others. Destroying Barlow has not saved Susan, who arrives at the house. She tries to tempt Ben into joining her but he resists. When Susan turns to attack Mark, Ben destroys her. Ben and Mark set the Marsten House alight, and during a chase with Charlie, who was vampirized by the town's children, a gas station is damaged and explodes. As fires spread through the town, Callahan vows revenge against Ben while the town's remaining vampirized population flock to him as their new leader.
As Ben concludes his story, the orderly realizes Ben was not acting alone. The orderly finds Callahan dead, suffocated with a pillow by Mark. Mark slips into Ben's room and tells him the vampire hunt is over. Ben suffers a cardiac arrest. The orderly finds Mark at a locked exit to the hospital and tells Mark he can't believe the story, but lets him go, indicating he may be struggling with actually believing it. Doctors battle to keep Ben alive as he begins passing away, finally at peace.
