Nate Thalmann wants to escape his life as a Prohibition Era bootlegger. He moves with his pregnant wife Alice to the Farallon Island lighthouse, situated on a rocky islet twenty-seven miles off the California coast. Joining three other keepers and their families, he hopes for peace and a deep reconnection with his wife. But one of the keeper's children finds a secret cave, and releases a malicious entity imprisoned within. It possesses a former keeper and soon the islanders are being stalked and slaughtered. The demon within the keeper plans to only leave Alice alive, at least until she's given birth to her child, who will become the demon's permanent vessel. With no radio, no resupply, and no weapons, it is up to Nate to keep his wife and unborn child safe. But the body-hopping fiend seems to always be one step, and one corpse, ahead of him. Will anyone survive wrath of the demon of Farallon Island?