Miami Metro follows up on a local convict's recent information regarding a 15-year crime spree.
With Deb having found all of Dexter's paraphernalia, including the blood slides, he has little choice but to admit everything. She decides not to arrest him or let the police know what he does during his off hours. She does decide she's going to try and cure him and keeps him on a very short leash. Dexter is wondering more and more what to do about Louis Greene who he is convinced sent him the hand from the Ice Truck killer case. Louis doesn't scare easily however. The police continue to press the investigation into Mike Anderson's death not knowing that Dexter has already taken care of the killer. They're raiding the strip club regularly and the owner comes to the US to take care of it personally. Meanwhile, a convicted serial killer offers to tell the police where some of his victims are buried. LaGuerta continues to research the blood slide she found at the site of the Marshall killing.
Dexter is forced to disclose his urge for blood to Debra after her discovery of his weapons and souvenirs. Debra decides to keep the secret and heal her brother. Dexter is forced to move to her house, since she wants to keep eyes on him twenty-four hours per day. LaGuerta secretly investigates the blood slide. Meanwhile Dexter is curious about Louis Greene and how much he knows about his secret life. Dexter finds a means to escape from Debra's surveillance when a serial-killer discloses the place where one of his victims is buried. Dexter is assigned to be there with the man and in the lunchtime he threatens Louis. Meanwhile, Angel and Quinn give successive raids in the strip clubs expecting to find an informer to give a clue to Mike Anderson's killer. However Dexter has killed Viktor Baskov and the owner of the strip clubs Isaak Sirko comes from Ukraine to know what happened to Viktor.
- Dexter is trying to calm Debra down following his second "big reveal," that he is a serial killer. He tells her he's been killing since he was 20 and only kills certain kinds of people. Dexter explains his dark passenger and his code. Even knowing the type of people Dexter kills Debra isn't sure what to do. She punches Dexter in the face and storms out.
At the office Debra looks up the Bay Harbor Butcher. She also reads that serial killers have a type of addiction and will continue to kill until caught.
Since Debra found the Ice Truck Killer hand in his apartment, Dexter realizes it can't be in evidence. While he looks, a panicky Masuka walks in and tells him about the hand being stolen. Masuka says he put Louis in charge of finding it. He's relieved when Dexter says he's not going to turn him in.
At Debra's next briefing the plan is to shut down the strip club twice a day until somebody tells them something about what happened to Mike Anderson. Debra tells them a murderer named Randall (who went on a multi-state killing spree with his girlfriend) now says he has evidence of an additional victim and wants to lead authorities there to clear his conscience. Dexter volunteers for the job, but Debra assigns Masuka.
Outside the station Debra tells Dexter she came very close to arresting him, but doesn't know what to do. Her plan is to conduct a kind of rehab for Dexter, which basically consists of him moving in and her watching him 24 hours a day.
Maria hears back from a private lab that the blood on the slide found in the church belonged to Travis. She instructs the person to keep everything very hush-hush and calls the FBI.
The guys shut down the strip club yet again and manager George Novikov (Jason Gedrick) is getting upset. Quinn hits it off with a dancer, Nadia (Katia Winter). She gives him the name of Kaja's bouncer boyfriend Tony (who didnt show up for work) and he leaves his card.
On the first night of serial killer rehab Debra instructs Dexter he'll be sleeping in her bed, while she sleeps on the couch. During spaghetti dinner Dexter says his need to kill starts with seeing blood, which eventually turns black. That night Dexter begins to research the plans of Louis' penthouse.
Quinn interviews Tony, who has little to say. But security tapes do back up his alibi for the night of her murder. Tony drops Viktor's name as the one who Kaja was with that night.
Masuka complains about the Randall case being mostly waiting around while the diggers try to find the body. Dexter volunteers to relieve him, but he needs Debra's permission. She's all set to go with him until Angel shows up with the info about Viktor, who is a member of Ukrainian organized crime.
While waiting at the dig site Dexter strikes up a conversation with Randall. Dexter asks about his change of heart. Randall says he decided to surrender.
Dexter sneaks to Louis' penthouse during lunch. While he's there he learns that Louis was the one who cancelled his credit cards. On the computer he finds several videos, one with Louis and a prostitute. He finds evidence that Louis probably framed a man in order to take control of his software company. Louis comes home unexpectedly. He sees his laptop open and Dexter pins him up against a wall, demanding to know why he's screwing with him. Louis says it's because Dexter trashed his video game. Dexter says he never wants to see him again, either at work or with Jamie.
Back at the site Debra is upset Dexter is running late. Randall notices the dispute and Dexter tells him about the boss/sibling dynamic. He asks Randall for clarification on the surrender line and he says once he stopped fighting it the anger went away.
After yet another strip club shutdown George goes back to his office to find Isaac Sirko (Ray Stevenson). Isaac clearly runs the organization and George is surprised he's in the U.S. Isaac believes George when he says he knows nothing about Viktor's disappearance.
Nadia calls Quinn and asks for a ride home from the club.
Maria has had the slides from the Bay Harbor Butcher case sent to her. She compares them to the one found at the church.
Dexter comes home and is surprised to see Louis there, hanging out with Jamie Batista (Aimee Garcia), flaunting the fact he's not scared of Dexter. Dexter thinks to himself that he needs to stop Louis.
After the ride home Nadia flirts with Quinn without giving him more information.
Dexter injects drugs into Debra's steak that night so he can sneak into Louis' place. He sneaks up behind Louis and knocks him out with a needle. Dexter takes Louis to a location, then seems to have second thoughts. He calls Debra and tells her he's seeing the blood. She arrives and he tells her he couldn't go through with it. She thinks he took a major step by calling her. After Debra leaves Dexter simply leaves Louis on a park bench.
Isaac and a henchman pay Tony a visit. After tricking Tony into admitting that he spoke with the police, Isaac sticks a screwdriver into his right eye socket, killing him instantly.
The next day Dexter and Debra are back at the Randall dig. When Debra goes to grab some ice cream, Randall talks about the fact he never got to patch things up with Hannah, the girlfriend with whom he committed his murders. He says Hannah only sees him as a killer. Randall says the clock has run out, then steps onto the highway and in front of a truck.