For the past decade, Dexter has been living a quiet, isolated life far away from the temptations of his past. He's found comfort in a new identity and has assimilated into small town life as a beloved member of the Iron Lake community. When a local hotshot begins behaving recklessly, and a mysterious stranger seems to be on Dexter's trail, he questions whether he can continue to suppress the murderous urgings of his Dark Passenger.

Dexter hopes to have a chance to make things right with Harrison, which is proving to be tough to do when there's a full-fledged crime investigation that Dexter himself has caused. Harrison joins the high school wrestling team and quickly makes a name for himself at school. Meanwhile, a true crime podcaster from LA arrives in Iron Lake and befriends Dexter's police chief girlfriend.