Dr. Vogel tells Dexter that Deb has become quite mortified when she attempted to kill him. Yet now that she has hit her all time low, things will begin to improve. Dexter isn’t that thrilled with Vogel and Deb and puts all his focus into finding A.J. Yates. However Deb and Dexter have another problem on their plate when Yates kidnaps Vogel, so they set out to her rescue. After rescuing Vogel and impaling Yates with a bedpost, she thanks them both for their heroism. The three of them talk about what had happened and Deb begins to accept the situation. At Metro Police, the cops are still trying to figure out just who the monster is that killed Norma Rivera. She had engaged in sexual activity shortly before her death so they assume who ever she had sex with was also the man who ended her life. They have a man in question, her former employer Ed Hamilton, who had admitted to having sex with her but insisted that she was alive the last time he saw her. Dexter begins to wonder if it was Hamilton’s son, Zach, who took her life from her. Vince Masuka finds out that Nikki is in fact his daughter and surely likes the idea of being a father and everything fatherhood has to offer. Quinn on the other hand warns Vince to be careful who he talks to and any “distant” relatives that begin to come out of the woodwork.
The next killer that Dexter goes after on Vogel’s list is a man named A.J. Yates who was placed in a mental health hospital when he was 15 years of age. Vogel tried desperately to channel Yate’s tendencies as much as she had with Dexter yet was unable to do so and ultimately failed in reforming him. When Dexter comes in contact with Yates, he notices a large scar on his forehead. He is later informed by Vogel that Yates had surgery to remove a brain lesion. Dexter breaks into Yate’s house and finds something of interest within Yate’s closet. Dexter is not alone in the house and it looks like he may be the man they are looking for. Dexter also finds something that will put a strain on his relationship with Vogel. Dexter meets a neighbor of Yates, named Cassie. The police have a victim, Norma Rivera, who Dexter believes was killed by someone close to her or by someone that she knew. Angel demands that Quinn, who has passed his exams, get down and solve this murder case if Quinn ever wants to make the Sergeant position in his police career. Masuka gets an unannounced visitor at the police station. Vogel begins her work with Deb trying to help her with her Post Traumatic Stress Disorder and they go and visit the very container in which Deb shot down LaGuerta. It seems as though Deb is making progress, but then doubt sets in.
The Brain Surgeon re-creates the crime scene where he slaughtered Sussman, placing his life less corpse on a meat hook, so that it looks like Sussman blew his brains out with a shotgun. This leads the police to think that it was Sussman who was the Brain Surgeon and killed himself out of repentance. He then sends pieces of Sussman’s brain, the optical portion, to Vogel labeled “His” and “Hers” letting Vogel and Dexter know that he is watching the both of them. Dexter proceeds to go through a list of Vogel’s ex-patients and comes across Ron Galuzzo, who had murdered his best friend when he was a child, but originally convinced Vogel that it was a bully who committed the crime. Yet this turns into a cold lead when they find out that Galuzzo is a cannibal. Meanwhile, Debra gets pulled over for a DUI, but Quinn helps her get out of it. Debra then proceeds to head to the police station with confessing to LaGuerta’s murder. Quinn calls Dexter and tells him what his sister is about to do. He and Vogel make haste to the police station to stop Debra and try to convince her that she is having survivor’s guilt. Dexter finds Debra within the interview room and when she tries to leave to make a public confession, he injects her with M99. Dexter then takes Debra home and asks Vogel to help her with her problems. At the conclusion of the episode, Dexter kills Galuzzo, calling him ‘Disgusting’ for being a man eater, even though he admits that the two of them are quite alike.
Dr. Vogel appears on Dexter’s door step and proceeds to show him a video tape she has that explains how she has the ability to know everything about him and where he came from. He finds out that it is in fact Dr. Vogel who had instructed Harry, Dexter’s father, towards teaching Dexter to funnel his murderous passion towards people who actually deserve it. She had developed the code, therefore developing Dexter. He does not look at her with fondness however, due to the fact that he has begun to hate his murderous urges at this stage and the lasting effect they have had on Debra. Vogel informs Dexter that the new murder in Miami is possibly one of her bygone patients. He thinks this because the murderer is putting samples of his victims brains in jars and leaving them on her doorstep. She feels deeply troubled by this and asks Dexter to take care of him for her. Dexter candidly refuses however. The Brain Surgeon in the meantime kills another victim with the help of a fall guy, and dumps the body. This time though, a fingerprint has been left at the crime scene. Unfortunately, this fingerprint in question belongs to Sussman, who was butchered by the Brain Surgeon and later framed for the crimes the Surgeon has committed. The Brain Surgeon then breaks into Vogel’s home and leaves her a DVD, containing the graphic and horrifying footage of him murdering Welks and Sussman. Both Dexter and Vogel come to the realization that this is truly happening all the while trying to keep it from Metro Police.