In 1957, insurance investigator George Lazarus is tasked with interviewing twelve employees of the Deadly Sin Cigarette Company when his firm receives a suspicious insurance claim. He learns that all twelve had been let go after contracting mysterious illnesses, but before he can report back, Lazarus goes missing without a trace. After his disappearance, his fiancée Bethany and his friend Chip set out to find him - but what they uncover may actually signal the end of the entire human race.

In Port City, North Carolina, a vagrant discovers plans for an invasion. His attempts to warn law enforcement are ignored but when the Sheriff notices odd interactions with other townsfolk, he begins to look into the claim of a sleeper cell living amongst the locals.