Dexter tries to bring Debra on board with his new target. While the Koshka Brotherhood seeks revenge for the killing of one of their own, Quinn grows close to a dancer at their strip club. LaGuerta, convinced The Bay Harbor Butcher is still out there, attempts to enlist Batista to help her re-open the Bay Harbor Butcher Case.
Dexter mails a package to Miami Metro Forensics with a plan to get rid of Louis. He fantasizes slitting one of the employee's throat because his Dark Passenger is growing stronger as Deb prohibits him from leaving the house at night. At a morning briefing, he fantasizes once more, this time stabbing Masuka in the neck. After the briefing, Dexter tries taking a DNA swab of a man under arrest, although he provokes Dexter into strangling him. Deb runs in before Dex can do any harm and she demands him to leave. Outside, he explains to her that if he doesn't live by Harry's Code and lives with Debra trying to suppress his Passenger, he will eventually harm someone innocent. Deb promises Dexter that she'll back off but tells him to hang in there.
Dexter looks over the file of Ray Speltzer, a man who was arrested but not convicted of the murders of two women. Dexter believes that Speltzer may kill again, and goes to his gym to vet him. He notes that Ray grew his hair out, but still looks strong and hostile. Nadia, a stripper at The Fox Hole, asks Quinn if he can retrieve one of Kaja's bracelets from evidence so she can be buried with it. Quinn tells her that he'll see what he can do, and Nadia returns to the Foxhole. Isaak tells her that if the police find the GPS chip in the bracelet, their operation will be ruined. He requests that Nadia grow closer to Quinn so that the bracelet can be retrieved, and they can find Viktor in the process.
Back at Miami Metro, the package that Dexter delivered earlier arrives. Vince opens it, and finds the Prosthetic Arm with intricate colored lines drawn on the palm. With it is a note which Dexter forged, saying:
"Dear Mr. Greene, When I bought the Ice Truck Killer's hand online I assumed it would be in mint condition, not with lines drawn all over its palm. Please refund all my money immediately."
Masuka fires Louis Greene for stabbing him in the back. Meanwhile, Wayne Randall's mother gives some of Wayne's possessions to Deb. Dexter looks through the trophies, one of them a necklace with Wayne's victim Janice's name on it. Dexter suggests that there may be more victims to match with all the trophies. Louis arrives back at his apartment where Jaime shows him a video diary of himself in which a hooker interrupts him midway through. Jaime tells him the tape was anonymously sent to her, and Louis tries to explain that it was probably Dexter. She dumps him and he begins to boil with rage. Dexter lures Deb to Speltzer's bar, Sugar Mill Saloon, where he explains that the newly bald man may kill again soon, describing his theory that shaving his head was a ritual of his killings. Deb tells him to lay off of Speltzer, and Dexter secretly plans on getting evidence to convince her of him being guilty.
Dexter investigates the cemetery that Speltzer works at, Briar Cemetery. Before he can pick a lock into a mausoleum which he believes is special to Speltzer, he gets a call from Deb to immediately report to her office. He confesses that he was stalking Speltzer at his cemetery, although assures her that he would have found the evidence had she not interrupted him. He pleads for her to let him break into the mausoleum because his "lizard brain" is alerting him that Speltzer will kill again. Deb assures him that she'll get a search warrant but Dexter worries that there isn't time. Later, Deb asks LaGuerta to get a search warrant on Speltzer's mausoleum, but LaGuerta tells her that assigning a patrol car on Speltzer is the most she'll do. At the Foxhole, a technician informs Sirko that the GPS on the bracelet was tracked going from Viktor's apartment, to the airport, to a marina, and then 8 miles out to sea where the signal disappeared. Sirko concludes that he was murdered and furiously demands the technician to pinpoint the exact position at the marina. Dexter and Batista are assigned to question Hannah McKay, Wayne Randall's partner in crime, and collect DNA from her, but they make a stop at the Foxhole first. Batista confronts George Novikov while Dexter has an ironic discussion with Sirko in which Dexter tells him, "I hope you find what you're looking for." At Hannah's nursery, Batista and Dexter are hastily and rudely addressed by her. She refuses to talk about her murders and she wants to move on.
At Dexter's marina, Louis Greene is in the process of sinking Dexter's boat. However, Sirko, Novikov, and Jurg show up and confront him. Greene tells them that he owns the Slice of Life, but after Sirko intimidates him will a drill bit, he shakingly admits that it belongs to Dexter Morgan. Sirko shoots Louis in the head, killing him, and demands Novikov to dispose of his body.
At night, Dexter breaks in to Briar Cemetery while Melanie Garrett simultaneously shows up at Ray Speltzer's house. Dexter finds one of Speltzer's trophies, an earring of one of his victims, in the mausoleum. He tries to send a picture of it to Deb, but the mausoleum has no cell service. Deb stakes out Speltzer's house and after she sees the lights go out in his house, she begins to leave but sees strobe lights commence in the windows. Meanwhile, Dexter receives a message from Deb about her investigating Speltzer, while leaving the mausoleum. In Speltzer's house, Garrett is chased through a freakish maze while he stalks her in a bullhorn helmet. Deb hears her screams and breaks in to the house. She confronts Speltzer but he knocks her to the ground, about to kill her until Dexter shows up and knocks him out with a plank. They find Garrett's lifeless body, and Speltzer escapes. Realizing that Garrett would still be alive had she let Dexter kill Speltzer, Deb is struck with tremendous guilt and remorse for the loss of life. She tells Dexter that even though she cannot condone what he does, she understands his "code", and she concedes that his activities might be a "necessary" evil.
- According to producer Scott Reynolds, the encounter between Dexter and Isaak at the Foxhole was not originally in the script. The scene was added because Michael C. Hall wanted an early meeting between the two characters.
- The metal song when Speltzer chases the girl is "Terror Metal - Dead and Gone."