When a young nun at a cloistered abbey in Romania takes her own life, a priest with a haunted past and a novitiate on the threshold of her final vows are sent by the Vatican to investigate. Together they uncover the order's unholy secret. Risking not only their lives but their faith and their very souls, they confront a malevolent force in the form of the same demonic nun that first terrorized audiences in 'The Conjuring 2,' as the abbey becomes a horrific battleground between the living and the damned.

A shuddering exorcism spins out of control and claims the life of a young girl. Months later, while working the night shift at the hospital morgue, Megan Reed receives a disfigured corpse. Alone and locked in the corridors of the cold basement, she starts to experience hair-raising visions, which lead her to suspect that the dead body delivered that night is possessed by a ruthless evil entity.

As the warm, bright sun refuses to set, and a series of equally perplexing events start to take place, the world, and the blissfully unsuspecting residents of the sleepy town of Centerville, are about to face the effects of corporate greed. Then, as the stone-faced police officers, Chief Cliff Robertson and Officer Ronnie Peterson, stop for doughnuts and coffee at the town's diner, unusual activity in the moon-lit cemetery and a blood-soaked scene of carnage could only mean one thing: this is the work of flesh-eating zombies. Before long, Officer Mindy Morrison and the glacially beautiful, katana-wielding undertaker, Zelda Winston, join the team of defenders, as hordes of relentless, ravenous undead swarm into the once-peaceful town craving meat. More and more, humans are at risk of becoming an endangered species. What happens when the dead just don't want to die?