 Dexter receives a voice message from his foster sister Debra Morgan (Jennifer Carpenter), a police officer in the vice department and, Dexter believes, the only person who loves him. Debra says she is at a crime scene and wants him to be there, because she needs his help. Dexter arrives and Debra, undercover as a prostitute, informs him that another hooker has been killed, the third in five months. Dexter inspects the victim and is shocked to learn that the chopped up corpse is bloodless. Dexter leaves, awed by the killer's technique, and says that due to the lack of blood he can't help out. At the police station, Dexter discusses another murder case being handled by James Doakes (Erik King), who hates Dexter and suspects he is hiding something. Dexter suggests that it was a crime of passion, rather than the bad drug deal Doakes believes it to be. Dexter surveils Jamie Jaworski, a murderer who escaped justice due to a faulty warrant, and breaks into his home to find proof of his crime. Once he confirms that Jaworski is guilty, Dexter meets with his girlfriend Rita Bennett (Julie Benz), a domestic violence victim. Because of her violent past with her husband, Rita has no interest in sex, and Dexter secretly feels comfortable with the lack of intimacy. Rita has two young children, Astor and Cody, whom Dexter genuinely feels for. While on a date with Rita, Dexter finds another crime scene in which the victim has been cut into pieces with no traces of blood; this time, however, the head is missing. Dexter theorizes that the killer murders his victims in extreme cold, explaining the absence of blood. Dexter further suggests that a stolen refrigerated truck is being used for the murders. Dexter allows Debra to pitch the theory, but their superior officer, Lt. María LaGuerta (Lauren Vélez), who dislikes Debra, dismisses it.
