In the city at night, there are always secrets that you can't imagine. Dexter Morgan (Michael C. Hall) is a hard-working forensic doctor. He is kind and humorous, popular, has a free and easy, boyish sister Debra (Jennifer Carpenter), and a gentle and beautiful girlfriend Rita (Julie Benz). Being in the police system, Dexter is able to fully hide his secret identity-a cold-blooded killer, and use his position to find the most heinous people who can escape legal sanctions. Outside the law, the real villain deserves the punishment. Dexter chose such a dangerous identity because of his painful experience when he was three years old-his mother was dismembered in front of him, the villain left, and he and his brother were thrown in a pool of blood for three days before being discovered. Dexter was meticulous and skillful in carrying out secret murders until his brother Brady, who had been sent to a mental hospital, suddenly appeared in his life...