Dexter Morgan and Arthur Mitchell are standing face-to-face in the homicide dept. Dexter berates himself for allowing Arthur to discover his name and where he works. Arthur tells Dexter to disappear from his life, then he and his family will be safe. As a parting barb, Arthur suggests, “If I were you, I’d give up vigilantism. You’re not very good at it.” Dexter watches Arthur casually walk to the elevator and close its doors.
Immediately, Dexter opens a locked drawer in his office and takes out a syringe of M99. As Trinity saunters out of the station, Dexter is hot on his heels. However, Joey Quinn stops him to sign off on Christine Hill’s blood spatter report. Arthur’s van is pulling out of the parking lot, so he promises Quinn to do it later. When Quinn remarks that Dexter is ditching work to chase some tail, Dexter throws him down on the pavement. Dexter gets into his SUV and quickly peels out of the lot, muttering, “Fucking mess.”
Arthur has a head start and Dexter is driving like a maniac trying to catch up with him. Rita calls to say that she wants her honeymoon this weekend, because Astor and Cody will be away at Disney World with Paul’s parents. Dexter, distracted, agrees with little objection. Rita signs off, promising to research flights and hotels. Unfortunately, while weaving in and out of traffic while driving with one hand, Dexter clips a guy’s driver-side mirror, and keeps going.
Arthur takes a left and pulls into the parking garage for the Stafford Bank. Dexter parks just outside, and watches Arthur walk into the bank. He positions himself behind the van, syringe at the ready. Unluckily for Dexter, the guy who had his mirror clipped pulls up next to Dexter’s car to wait for him.
Back at Miami Metro, Debra Morgan is standing at the Trinity white boards. Three of Christine’s postcards — from Topeka, Cheyenne, and Bloomington — do not have matching murders and Deb wants to call law enforcement in those three cities. Her voice is shaky because Christine committed suicide in front of her a few hours ago. Angel orders her to go home and promises to check those cases out himself. Maria LaGuerta strides in and asks what Deb is still doing there. Angel Batista talks about work while LaGuerta just stares at him. Newly married, they decide to move in together.
Arthur returns from the bank with a fat manila envelope. When he gets to the van, Dexter injects him and loads him into the back. The envelope contains a large amount of cash, and Dexter realizes that Arthur has closed all his accounts, about to skip town and leave his family destitute. This benefits Dexter because when Homicide figures out that Stan Beaudry isn’t The Trinity Killer, they will assume that Arthur’s left the country.
Suddenly, Dexter spots Mirror Guy standing next to his car with a couple of cops from the sheriff’s office. Dexter puts the money back in the envelope along with Arthur’s wallet and keys. He exits the van, stashes the envelope on top of a fluorescent light fixture, and walks out of the garage.
Mirror Guy is furious. Dexter calmly tells him it won’t help to be rude. He pulls out his Miami Metro ID and claims he was heading to a crime scene. Mirror Guy is skeptical and reminds him that no one is above the law. Dexter offers to pay for the damage, implying the matter should just be let go, but the officers aren’t impressed. They say he fled the scene of a crime, and they are not his buddies from Miami Metro. It’s at this point that Dexter’s accuser starts filming the confrontation on his cell phone. Dexter loses it, grabs the phone, and throws it to the ground. The cops pin him down, cuff him, and take him in. Arthur stays undiscovered in the van, and Dexter is uncertain how long he will remain unconscious.
Deb and Valerie are in a residential area of Miami in search of the mysterious C.I. Deb calls Harry a man-whore; Valerie agrees, but says he always made her feel safe. When Valerie finds the house, Deb recognizes it. It’s the same house where Deb almost met her death at the hands of The Ice Truck Killer. Deb states that Brian Moser brought her there, and Valerie chirps, “That was her name! Laura Moser. She had two little boys.”
For the first time, Dexter finds himself in a jail cell, and admits he has let Arthur live too long. At the garage, he had to follow the number one rule of the Code -- “Don’t get caught.” They were going to catch him with Trinity, and Dexter can’t let that happen. He needs to kill Trinity himself, to know he’s gone — for his family. However, Dexter can’t think clearly because of his family.
The Homicide team has gathered info on Stan Beaudry, and none of it supports him being The Trinity Killer. Angel enters with a serious expression on his face, and positions himself in front of the group. He has just spoken with the chief of police in Bloomington where three deaths in the summer of 1992 fit Trinity’s pattern. The police chief calls that summer the worst of his life because, five days before the bathtub kill, a ten-year-old boy went missing. LaGuerta remembers the missing boy, Scott Smith, from last week. Angel has called a few more cities and discovered what Dexter already knew. It’s not three kills per cycle -- it’s four.
Deb is at home reading the original newspaper report of Laura Moser’s death and learns that she was survived by two sons, Brian and Dexter.
Back at the county sheriff’s office, Dexter is go due to overcrowding. Their professional courtesy came through, but not how he hoped, since they had called Rita to pick him up. She is waiting for him, looking aggrieved. Dexter wonders, “How is it I can kill people and feel no regret, but disappointing Rita makes me feel like the scum of the earth?”
In the car on the way home, Dexter apologizes and says that he had a bad day. Rita lists his recent acts. Breaking the light. Punching Elliot. Picking a fight with the sheriff. She asks him to try and explain. He attempts with, “Sometimes I’m just going along and everything seems okay, and then this darkness creeps in and it takes over.” Rita says that makes him sound crazy, but she doesn’t believe he is. She drops Dexter off at the parking garage and he promises he’ll be right behind her. As soon as she’s gone, Dexter runs to Arthur’s van to see if he’s still there. He’s not. Dexter grabs the envelope with money, wallet, keys...and runs.
The Mitchells are enjoying a meal in Arthur’s absence, and discussing the possibility of Rebecca going to the winter prom. Arthur barges in and the change is immediate. Sally jumps out of her chair and begins to apologize for starting without him. He demands that she bring him all of her jewelry and any cash in her purse. It includes her wedding ring, but she balks, “This is mine.” When Arthur lunges for her, Jonah lunges to stop him, but Sally calms them both by handing over the ring. Arthur demands that Rebecca get the money she hides behind her headboard. “What did you do?” asks Jonah, who has probably been suspicious for a while. Arthur snarls that Jonah is lucky he doesn’t pull the fillings out of his teeth. “Someone stole something from me,” he growls, “and I’m gonna find him.” As soon as Arthur is out of the room, Jonah urges his mother to leave, but she won’t, because she believes they would live in fear. “We already do,” Jonah protests.
Deb pays a visit to Deputy Chief Thomas Matthews, to talk to him about an old case of Harry’s. When she says “a triple homicide down at the ports,” he knows immediately that she’s talking about Laura Moser. He still remembers Harry’s face when he got back from the crime scene. Deb absorbs that, then confirms what she suspects: Dexter Moser is Dexter Morgan. She goes on to say that Brian Moser became The Ice Truck Killer, but Matthews betrays no surprise. He already knew. He explains that Harry kept them in the dark to protect them and, considering how well they turned out, it looks like he made the right call. Matthews says she should keep it to herself. Deb’s been ignoring Quinn’s texts during this time but, when he calls again, she loses patience and answers rudely. He wants her downstairs, and she leaves to meet him.
Arthur is at his computer in the garage, looking up Dexter in the White Pages. He finds a listing for D. Morgan and cackles gleefully.
At home, Dexter peers warily through the blinds in his bedroom window. “We should go to the Keys tomorrow,” he tells Rita, “for our honeymoon.” He wants her to leave tomorrow with Harrison, and have a spa day. He promises to meet them after work. Dexter thinks she’s upset at having to pick up another husband from jail, but Rita’s just afraid of losing him. Dexter kneels at her feet, and Rita tells him that she accepts his demons, and knows he can overcome them. He doesn’t believe her. Dexter buries his face in her lap, then her chest, then kisses her and says, “I want to be that man.” He begs her to fly to the Keys tomorrow morning, and they roll together on the bed.
That same night, Angel removes the photos of Beaudry from the “Trinity suspect” box. They’ve decided the real Trinity planted all of the evidence, including Frank Lundy’s books. Angel has spoken with law enforcement in almost every Trinity city and, in every one, a ten-year-old boy went missing five days before a bathtub murder. Angel wants Quinn to interview Scott Smith, but Quinn choses “someone who knows about being kidnapped.”
Deb sits across from Scott and his father and says she was once kidnapped, too. As much as she tries to forget it, she keeps remembering a bunch of little things. She asks Scott if he remembers any little things, too. He remembers a picture on a flyer, so Deb hands him some paper and a Sharpie. When he’s done drawing, she rushes out and tapes it to the Trinity boards. It’s the Four Walls One Heart logo.
The homicide team descends on a Four Walls build site and the cadaver dogs find a buried body bag. Vince Masuka climbs into the pit and rips the bag open, recoiling from the smell. It’s a gray and shrunken corpse. Vince reports that the victim looks to be about ten years old, and is wearing pajamas. LaGuerta goes off to get a warrant, and Angel orders Deb to start a list of everyone who has ever volunteered for Four Walls One Heart, nationwide, and cross-check them with Trinity cities.
Arthur picks a lock and walks into Deb’s apartment. Arthur disparages the mess, and then becomes upset to find a bra on the floor. He goes through the mail. “Debra Morgan? Fucking Debra!” he screams, throwing the mail to the floor.
The next morning, Astor and Cody leave for Disney World in their grandparents’ car. Soon after, Rita and Harrison, are waiting in a taxi while Dexter bounds towards them with a favorite toy. Dexter promises that he’ll see her tonight, after he ties up a few loose ends.
On the hunt for Arthur, Dexter goes to the Mitchells’ house. Jonah reports that he was there yesterday looking for anything he could sell. No one has any idea where he might have gone, if he’s packed a bag, or if he has a passport. Suddenly, they hear a helicopter hovering above the house. Peeking through the blinds, Dexter sees a SWAT team rounding the hedge. Cursing, he dashes out, just before the men break down the front door and force the family to the floor.
Meanwhile, Dexter is hiding in the garage inside Arthur’s handmade coffin. He climbs out just in time to show the SWAT man his forensics badge. The garage door opens to show Deb and Angel in flak jackets, staring at him dumbly. He distracts them by pointing out the coffin and the outline of the framing hammer. Deb is looking weirdly at Dexter. She says they found Trinity through the Four Walls database, and that he’s abandoned his family. Dexter appears surprised. Deb snaps at him to put on his flak jacket.
Heading out of the garage, Dexter is confronted by Quinn, who refers to him as “the fucking karate kid.” He promises that the next time Dexter gets physical, he’ll react differently.
The Mitchells are being led out of their house, the females crying. In Dexter’s mind, they become Rita and the kids, and they’re being led to the cop car by Harry in his old-school police uniform. Dexter realizes that if he is ever caught, he’ll be executed, an his family will live with the shame for the rest of their lives.
Deb calls to Dexter from the front porch. Despite Matthews’ warning, she wants to tell him the truth about his origins. He listens, filled with dread, but is relieved that she only knows his mother’s name and his brother’s identity. He acts shocked, saying it’s a lot to take in. Dexter reassures Deb that what happened with Brian Moser was not her fault, and Brian must have attached himself to her get to him. Dexter says it wouldn’t have happened if he hadn’t been in her life. Deb angrily retorts, “If you hadn’t been in my life, I wouldn’t be who I am.” She’s called away by Quinn, but first tells Dexter that she loves him. He responds by saying he’s “grateful.”
Walking away, he sees the Mustang’s smashed windshield and knows in an instant where Arthur must be. He would never leave that car behind. Checking Arthur’s wallet, Dexter finds a receipt for Julio’s Autobody.
Julio himself escorts Arthur to the Mustang, which has been painted black. Arthur commends Julio on his beautiful work. In spite of the fact that the paint “needs more dry,” Arthur hops in and peels out, ignoring Julio’s protestations. Arthur drives out of the city, listening to salsa music. He laughs as he breaks the city limits.
In the briefing room at Miami Metro, Angel reports that Sally Mitchell had no idea what her husband was up to, and she vomited when confronted with pictures. Vince waves his hand and states, “That can be faked.” Guys from the FBI walk in, accompanied by Deputy Chief Matthews. Agent Davis commends LaGuerta on her work, and she justly hands most of the credit over to Deb. Quinn backs Deb up as she lets them know they dropped the ball by ignoring Lundy’s work. They admit they can see that, in retrospect, and Deb reminds them that “your retrospect cost a man his life.” The FBI then takes over the case, and all the credit. Deb watches them as they dismantle their months of work, then looks at the floor, turns, and walks away.
Mist is settling down around the palm trees as Arthur cruises down a deserted country road, listening to fifties music. The engine sputters and starts to smoke, and Arthur pulls over, muttering, “Damn it to hell.” Opening the hood, he wonders where his oil cap has gone. Dexter steals up behind and slams the hood onto Arthur’s head. He knocks him down and, holding the oil cap in his hand, says, “Hello, Arthur Mitchell,” before tossing it aside and capturing the man who is whimpering on the ground.
Arthur wakes up immobilized by plastic wrap, staring at the photos of his many victims. The model train set is on the floor. Turning his head, he sees Dexter perched nearby watching him. Arthur claims to have been following his path, that God led Dexter to him. “Hardly,” says Dexter, slicing Arthur’s cheek. Arthur admonishes him for so clearly taking pleasure in killing, something that he himself never did. Dexter coolly agrees that Arthur is a special kind of monster; nevertheless, he destroyed his family. Arthur didn’t know that his daughter, Christine, was dead, but dispels his grief by dismissing her as weak. Dexter chides himself for thinking he could learn something from Arthur. Dexter says he’s no better than Arthur, but wants to be. Arthur warns Dexter that he’ll never be able to control his demon. He claims to have tried by praying to be changed. Dexter retorts, “That’s not trying. That’s just waiting to be stopped.” Arthur points out that it worked. Dexter asks for advice on what he can do -- leave, disappear, fake his own death and start over? “No point,” Arthur says. “You’ll still be you.” Dexter insists that he’s good for his family, but there is doubt in his voice. Arthur requests that Dexter start the model train and he does. He also drops a record onto the player and Arthur sings along. Then Dexter holds a framing hammer over Arthur’s head and turns it so the claw side is down. Arthur lifts his chin, and Dexter strikes.
On the Slice of Life, Dexter dumps the pieces of the prolific serial killer into the Gulf Stream. He looks up at the full moon and wonders if Rita is looking at it too. Dexter feels it’s time to embrace the light, embrace his family. He hopes that one day he’ll be rid of his passenger entirely. He just needs some time away from the old Dexter.
Dexter, arriving home to family photos and toys, considers the importance of living his life. He grabs his luggage and drops his briefcase. His phone beeps with a message from Rita. She forgot her ID and had to return home to get it, so they will arrive a little later, and wait for him in the Keys. She also tells him that the moon will be amazing. He calls right back, perhaps to tell her he’s looking at it, too.
He can hear Rita’s phone ringing. It’s in her purse, and her purse is on a kitchen chair. As he holds both phones in his hands, he hears Harrison cry. With mounting fear, he follows the sound to the bathroom. He turns on the light and finds Harrison sitting in blood on the floor, wailing. Rita is lying in the bathtub, dead in a pool of bright red water. Dexter checks her pulse, and closes her eyes. As he picks up his blood-spattered son, he sees himself at three years old, covered in blood, being swung over Harry’s shoulder. He realizes that Harry was right. He can’t change who he is.
- "Born in blood... both of us. Harry was right. I thought I could change what I am, keep my family safe. But it doesn't matter what I do, what I choose. I'm what's wrong. This is fate." - Dexter, at the end of the episode