Dexter Morgan, a Miami Metro Police Department blood spatter analyst, is living a double life. After his day job with the police department, Dexter moonlights as a serial killer, hunting and killing criminals who slip through the justice system. Dexter's sister, Debra, a vice squad officer, pulls Dexter into her world when another serial killer is killing prostitutes and leaving their bloodless bodies dismembered in various locations around Miami. Meanwhile, Dexter hunts a man who made snuff videos and killed a mother of two.

The Ice Truck Killer leaves severed body parts from his victims at locations that are linked to memories from Dexter's troubled childhood, which begins to get into Dexter's head.

The Ice Truck Killer leaves a clue at the scene where Dexter has dispatched his latest victim, and Dexter is worried that someone might have witnessed his killing. Rita is trying to deal with her ex-husband.

While on a weekend getaway with Rita, his sister and her new beau, Dexter learns that his biological father, thought to be dead for 30 years, has just passed away, and that he's willed his son everything he owned.