John Milton (Nicolas Cage) is an undead criminal who has broken out of Hell and stolen Satan’s personal gun, labeled The Godkiller to kill Jonah King (Billy Burke), a cult leader who tricked Milton’s daughter into joining his followers in the wake of Milton’s death 10 years prior, only to kill her and her husband and steal their daughter (Milton’s granddaughter) to be sacrificed in a Satanist ritual. King believes that if he kills the baby, he will unleash Hell over Earth.

After interrogating and murdering some of King’s followers, Milton discovers that the ritual will take place in Stillwater, an abandoned prison in Louisiana. He heads there, but stops by a diner, where he meets Piper (Amber Heard), a waitress. Milton’s car is damaged in the pursuit, so he sabotages Piper’s car, a 1969 blue Dodge Charger R/T 440 and follows her to fix it in exchange for a ride on the way to Stillwater to find King.