Working as a blood-splatter specialist in the Miami police department, Dexter Morgan is used to seeing crimes—especially because, whenever possible, he commits them himself. Guided by his Dark Passenger (an inner voice), outwardly he lives a normal life, following one simple rule: he kills only “bad guys.” But Dexter’s happy existence is turned upside down when he’s called to the scene of a crime on a campus. Dexter’s Dark Passenger immediately senses something familiar—something deeply oppressive—and the Dark Passenger, the master of Dexter’s mind and a heroic killer, hides.
For the first time in his life, Dexter is left alone, and realizes that he’s going to hunt a truly sinister rival. Meanwhile, he is planning a wedding and trying to learn how to be the stepfather of two children of his fiancée—children who might also have their own dark sides.