Dexter investigates when the Ice Truck Killer strikes again, killing the prosthetic arm prostitute and leaving her body before a Christmas tree in Miami's Santa's Cottage. Sgt. Doakes continues to grow more suspicious about Dexter after catching him in a series of lies about his connection to the Ice Truck Killer. Dexter finally finds a connection between him and the Ice Truck Killer over a past case involving Harry Morgan and a bloodbath crime scene back in 1973 involving Dexter's biological mother. Meanwhile, Lt. Maria Laguerta braces herself for dramatic changes in the department when the officious Captain Matthews maliciously makes her the scapegoat for the department's failure in the case to find the Ice Truck Killer, and he has her replaced. Rudy and Debra spend some quality time together in which he proposes marriage to the smitten detective. With Angel in the hospital recovering from the stabbing, his estranged wife pays a visit, while Rita decides to take her children, Astor and Cody, to visit Paul who's now back in prison.
Dexter argues with Rita's because of her desire for them to move in together before they get married. While playing golf together, Miguel tells Dexter about a husband who he has been unable to convict over killing not one but two of his wives for financial gain. Dexter sees him as the perfect candidate for his "dark passenger" and his needs, like any man under with relationship problems, to get away. Dexter tracks the murderer to Bimini however, while on the hunt, Rita has a medical emergency and he is nowhere to be found. Meanwhile, Debra works with Anton, her confidential informant to track down one of Freebo's criminal confidants. But Debra is finding herself oddly attracted to Anton.
Now that Rita has agreed to marry him, Dexter isn't so comfortable with all that it entails, especially when she suggests that he give up his apartment and that they buy a house together. Rita is uncomfortable when Dexter says he plans on keeping his apartment even after they are married. Meanwhile, Miguel Prado tells Dexter about Ethan Turner, a man who seems to marry for money and then conveniently disposes of his new bride. Prado has been unable to nail him. Dexter researches the case and decides that Turner will be his next victim. Only problem is that while he is taking care of him, Rita has to be hospitalized. When Miguel learns that Turner is missing, he puts two and two together and asks Dexter point blank if he killed him. The squad is less than thrilled when the volatile Ramon Prado is assigned by the Sheriff's Department to liaise with Miami Metro on a murder case that he thinks is related to his brother's case.
By J. Spurlin:
Through Miguel, Dexter learns of a wife-killer who has gone free - the perfect person for his next kill. As Dexter pursues his private passion, Rita has complications with the baby and ends up in the hospital. Miguel and Sylvia are there with her - but where is Dexter? Meanwhile, Debra works with Anton to track down Freebo and eventually learns about Wendell, a teenage boy who used to act as Freebo's door man. A suddenly suit-and-tie-wearing, overly polite Masuka gets on everyone's nerves.
By Claudio Carvalho, Rio de Janeiro, Brazil:
Dexter and Miguel go to a golf club and the ADA tells Dexter that his hands are tied by the law in the case of Ethan Turner, a killer that has murdered his wife to get her money and disposed her body in international waters while sailing. The criminal has escaped from justice due to the lack of evidence. Dexter concludes that Ethan has targeted him as his next victim. Meanwhile, Rita and Syl begin house hunting and Dexter argues with Rita. Debra is investigating the disappearance of Freebo with informant, Anton, and they meet Tilly, a junkie who gives them information about the Wendell, Freebo's watchman who saw Dexter. Ramon becomes the liaison between his department and Miami Metro in the investigation of a murder case and Masuka wins the respect of his team with his observations about the crime.
Dexter's failure to dispose of Little Chino results in the tragic death of a witness against him. He's determined to get it right the next time, but Sgt. Doakes is still following him in his off hours. With the discovery of Dexter's burial ground, a special joint task force with the FBI is established. Doakes hopes to join but is rebuffed. Debra Morgan clearly has not recovered fully from her ordeal with the Ice Truck Killer but her use of excessive force results in a major drug bust. Rita is having trouble coming to grips with the death of her husband and she now realizes that Dexter set him up. In order to explain however, Dexter embellishes his story somewhat.
By J. Spurlin:
Dexter, desperate to get his game back, seeks out Chino yet again; but the hulking gangster is waiting for him. Dexter's troubles accumulate as Agent Lundy from the FBI comes to Miami Metro PD to help them track down a newly-discovered serial killer, dubbed the Bay Area Butcher. Dexter is displeased with his lurid new moniker. Meanwhile, Sgt. Doakes tries to get on Agent Lundy's team. Debra, who is still living with Dexter, finds she is not back to normal when she freaks out over a young spray-paint vandal. Esme continues to confide in Debra with her fiancé troubles. Rita and the children mourn Paul, as Rita becomes increasingly suspicious of Dexter.
Deb is going through a particularly bad patch and there is nothing Dexter can seemingly do about it. A cop finds her behind the wheel of her car, drunk. She had the good sense to pull over but ran over a parking meter in the process. She contacts Quinn who manages to get her out without being charged. Dexter blames himself but Vogel says he shouldn't take on her problems. She also wonders why Dexter didn't kill her when she found out about him. Drunk again, Deb goes to the station and tells Quinn she killed LaGuerta. Meanwhile, Dexter and the police check out Lyle Sussman's cabin only to find him dead on the floor, the victim of a shotgun blast through the mouth. Dexter is wondering if he was the real killer or if someone else was manipulating him; perhaps that someone also killed him. As far as the police are concerned however, the Brain Surgeon case is officially closed. Vogel continues to receive threatening messages, this time two package with brain matter labeled his and hers. Ron Galuzzo is the next of Vogel's patients Dexter investigates. Dexter is convinced he's their man and breaks into his house. Yet even Dexter is not quite prepared for what he finds.
By Claudio Carvalho, Rio de Janeiro, Brazil:
Debra is downhill in her life, drinking too much. She is arrested for D.U.I. and calls Quinn in the middle of the night to release her without being charged. Meanwhile Dexter and Dr. Vogel try to find who might be threatening her and Dexter investigates her former patient Ron Galuzzo. The serial-killer sends two pieces of Sussman's brain, one for Dr. Vogel and the other for him. Dr. Vogel is intrigued with Dexter, who is consumed for loving Debra, and offers to help her, but Dexter tells that he can fix his problem since he is Debra's problem. He has dinner with his sister but Debra feels consumed by guilty for killing LaGuerta and she goes to the Miami Metro to confess her murder. However Quinn summons Dexter and he takes Debra home with Dr. Vogel that will treat her. Dexter discovers that Galuzzo is not the killer that is threatening Dr. Vogel but he has a dark secret.