• WARNING: Spoilers

    {{This synopsis covers the story arc of all eight seasons. Without naming names, it still spoils storylines. It is provided as a reference for viewers who have seen the show from beginning to end.}}

    Dexter is a serial killer with a "code" which directs his compulsions to kill only the guilty. As a blood spatter analyst for the Miami police, he has access to crime scenes, picking up clues and checking DNA to confirm a target's guilt before he kills them. His dead adoptive father Harry, a policeman, created the code after recognizing Dexter's problem when he was very young. Harry decided to teach Dexter to focus his urges on killing killers who would otherwise escape justice in the legal system. He creates the steps Dexter must take to keep from being caught. In the present, Harry sometimes serves as his mental partner, discussing cases and always reminding him of the code. Before his death, Harry had also charged Dexter to take care of his stepsister Debra - she is unaware of Dexter's secret and his complete lack of feelings, but they try to be close to each other.

    Season one features the Ice Truck Killer, who intrigues Dexter personally. The killer finally reveals their surprising connection, but when he seizes Debra, Dexter has to kill him.

    In season two, the bodies Dexter had been dropping from his boat are discovered. He scrambles to cover his tracks as the department searches for the Bay Harbor Butcher. He is drawn to a woman who eventually reveals her sinister side. In the finale, events allow Dexter to frame a dead police department member as the Butcher.

    In season three Dexter is ready to kill a target, but is surprised by another man in the house. Dexter is forced to kill him, but it turns out he is related to a public official. Rita announces she is pregnant. As Dexter pursues The Skinner killer, a person discovers Dexter's secret and begins ordering Dexter to kill certain people. Dexter marries Rita.

    Season four features the Trinity killer, as well as Dexter's exhaustion facing the demands of being a husband and father. The season ends with the death of a major character.

    Season five revolves around the Barrel Girl murders. Dexter finds and releases the only victim who lived, and she insists on helping him take down the guilty men. Dexter enjoys her company, but at the end she explains she has achieved her goal and will walk away from their relationship. Without knowing their identities, Debra tracks them down but decides they have done the world a service, and lets them go free, sight unseen.

    Season six focuses on the Doomsday killer, who connects his kills to religion. In the season finale, Debra walks in just as Dexter stabs the killer.

    In season seven, Dexter admits to Debra that he is a serial killer. LaGuerta privately re-opens the Bay Harbor Butcher case. The Ukrainian mob becomes a special nuisance. Hannah McKay also appears, but Dexter ultimately lets her go free. In the finale, Debra is forced to kill an innocent person to preserve Dexter's secret.

    In the final season, Debra is a shambles from her guilt. Dr. Vogel, a psychologist who specializes in psychopaths, joins the police pursuit of The Brain Surgeon, and privately reveals to Dexter her past connection to him. Meanwhile, Dexter forms a serious relationship with a woman from his past. He realizes he is experiencing emotions, and that his need to kill has vanished. They decide to take Dexter's son and leave Miami forever. In the season finale, a major character dies and Dexter realizes he has destroyed everyone who came in contact with him.