She is Dexter’s deceased sister who was a cop in the Miami Metro Police Department, and possibly the only person he truly loved. Deb re-appears in a new iteration to challenge Dexter in every way possible in a corner of Dexter's mind.
This version of Deb isn't a ghost, but more of a link or an echo or an inconvenient truth for Dexter (per Jennifer Carpenter). She represents how far Dexter has fallen without a compass (per Michael C. Hall).
Deb is Dexter's moral compass, appearing in his mind to nudge him in the right direction. When he first sees Harrison as a teenager, Deb encourages Dexter to pretend he's not really Dexter and to turn Harrison away. She says “You can’t, everyone close to you dies, that’s why we’re here.”
Deb also praises Dexter saying he’s a changed man now - almost ten years without a kill.
Dexter has invited his son back into his life, but he's conflicted. Deb persistently taps on a window with a gun bullet until Dexter shouts, “Stop!” and the window shatters. Deb furiously yells. “You’re not listening!” and calls him a selfish psycho and an emotionally handicapped crazy fuck, who will fuck up Harrison - if he doesn’t end up getting him killed. She then forces the bullet into Dexter’s mouth.
Dexter drives through the forest “searching for Matt” but really covering up the blood trail that leads back to his cabin. Harrison notices the dead white deer and Dexter sends him back for Angela. Now alone, Dexter looks for Matt’s blood in the snow. Amused Deb comments, “They always say killers return to the scene of their crime, but this is fucking ridiculous.” Dexter finds the bloody rock on which Matt hit his head and cleans it with Windex. Deb laughs and says it won’t solve his problems. She adds, “[Harrison] has your brain. He's smart enough to know that people don't fake their fucking death if they have nothing to hide! Who the fuck do you think you're fooling?!” She laughs again. Dexter insists that the “Matt thing” was a one-time screwup and then throws the rock into the distance. Deb asks, “What the actual fuck do you think you're doing? Harrison's been here one day, and you have him in the woods looking for a man you killed? He'd be so much better off without you.” As Dexter runs to a spot to plant Matt’s glove, he thinks, “He's my son. I lost him once. I won't lose him again.
When Dexter notices Harrison taking it upon himself to make friends, Deb says, “Well, he's not an awkward-as-fuck budding serial killer like you were.” She doesn’t think Harrison should be around Dexter, but he insists that he’s safe with “Jim Lindsay.” Deb retorts that he sounds like the old Dexter; he loves getting away with murder and can’t wait to kill again. In his head, Dexter yells, “Stop!”
Later, when Dexter hands Angela a cup of tea, Deb mocks him for being a “smug fuck” for getting away with the murder.
Harrison and Jim (Dexter) meet with Principal Strode on Harrison's first day of school. When she asks why Harrison was placed in the foster care system. Deb appears, dressed as Strode, and needles Dexter, "Yeah. Why don't you tell them why you left your beloved son?" Harrison explains that his stepmom had died and they had just moved, so his father had no way of reaching him.
Dexter learns from Angela that search dogs are arriving the next day. Deb swears and warns Dexter that he needs to move Matt's body because the dogs will walk a straight line from the crime scene to his firepit. She angrily reminds him that it's not just about him anymore and holds a gun to his head. Dexter insists that it was a one-time slipup and it doesn't change who he is now. When he orders Deb to stop berating him, she asks, "Or what? You gonna kill me again? Or are other people gonna die? Because that's what always happens, right? Right?!" Dexter promises, "Not this time. No."
After Dexter drops Harrison at school, Deb agrees that creating the false scent trail was smart, though it's not gonna throw them off forever. He asks for ideas and she says, "This town is small as fuck, but there's got to be someplace to hide a body. What about your lake? Just like old times." Dexter says that it's too shallow and some fisherman is liable to catch a piece of Matt. Deb suggests Iron Lake Cemetery but he says the ground is too frozen this time of year. Deb then states, "Oh! I know!" as she throws body parts into a woodchipper. Dexter remarks, "Little Fargo, don't you think?" When he notes that none of these places will work long-term, Deb outraged, asks, "What the shit do you mean 'long-term'? Are you planning on fucking killing again?" Dexter clarifies his comment. 'No. I mean, over time, the body parts will be discovered. All I want is everyone off my property, a good night's sleep, and a chance to make things right with Harrison. It's one and done. Then I'm just a dad."
Dexter debates with "Deb" in his head about Kurt Caldwell's true intentions behind saying his son is alive. Dexter thinks he had some sort of delusion. Deb, though, believes Kurt is lying because he wants Angela to close the case so that he can kill Johnny Bullhorn later on, believing that Johnny murdered Matt for shooting the deer. Or Kurt might discover that Dexter is the real killer.
At home after the stabbing incident, Harrison wants to know if Dexter ever had a situation that scared the shit out of him. There's a flashback of the Shipping Yard Massacre and Dexter answers, “Yeah.” Harrison asks, "What do you do to deal?" I wrap bad guys in plastic and kill them, Dexter thinks, but he stammers, "I'm not sure." Seemingly disappointed, Harrison says he's fine and refuses to talk more about it.
Dexter is irked by Deb: "Aw. Who's the world's greatest dad? Man, to think, from the moment he was born, you were worried that he would inherit your fucked-up genes. But... he's emotional, he's empathetic, personable, popular, heroic even. And you're so different. It's gonna be impossible for you to have a relationship with your own son."
Harrison becomes defensive when Dexter questions him about how he was stabbed. Dexter tells Deb that the stab wound doesn't match the story and something's off. Deb retorts, "You're off. He's normal. Details get mixed up. Normal people, you know, fuckers who aren't mental cases, they get rattled when crazy shIt happens." Dexter hopes that she’s right and Deb asks, "Do you?"
Dexter goes to the school to make sense of Harrison's story since the angle of the penetration of Harrison’s wound and the blood spatter doesn’t match. Deb scoffs, "Everything he said about Ethan turned out to be true. The kill list, the weapons. It all adds up." Dexter hands a knife to Deb and says, "Prove it. You're Ethan. I'm Harrison. Show me what happened. Do it. Harrison's lying."
Deb angrily says, "You can't handle the fact that Harrison is a hero. That was always your wet dream." [Multiple Debs cheer Dexter as a marching band plays.] "And you can't stand the fact that he's living it, because you are a jealous, fucking pussy." She rushes at Dexter and stabs him. He pushes he hand away, points to the blood on the floor, and says, "Blood doesn't lie. The spatter doesn't match. How do we recreate these patterns? This time we see if Harrison attacked Ethan first."
Deb shouts, "You're trying to make him into a monster, like you. 'Cause that's the only way you can feel like a real dad, right? Is if he looks up to you and wants to be like you so you could have some sick-ass serial killer family. He's a good kid. He's nothing like you. I am so sick of your bullshit." Dexter suddenly slices Deb's leg and she falls to the floor, bleeding. When the blood matches, she shouts, "Stop it! This is all in your head! You are creating this!"
Then Dexter stabs himself, assesses the blood pattern, and confirms that Harrison attacked Ethan from behind and stabbed himself to sell his story. In disbelief, Deb asks why Harrison would slash Ethan first since he didn't hate him. Dexter thinks Harrison wanted to know what it felt like to stab someone.
Later, Dexter picks through Harrison's things, looking for any troubling signs and finds a straight razor hidden in a flashlight. Deb sobs, "Trinity used a straight razor to kill his mother. He was born in blood, just like you." Believing that Harrison has his Dark Passenger, Dexter seems both relieved and distraught.
Dexter opens the straight razor he found hidden in Harrison's room. Deb asks, "Do you think he remembers?" Dexter says he can’t. Deb reminds Dexter that he remembered when drug dealers dismembered his mother. She doesn’t want Harrison to become a killer, or even learn that his father is one. However, Dexter thinks he should be honest so he can guide his son through what he's feeling. Deb, outraged, responds, "What are you gonna tell him? There are a hundred garbage bags with chopped up human beings at the bottom of the Atlantic Ocean? What the fuck do you think that would do to him? He'd turn out worse than you, and you are a fucking monster!?
Harrison is released from the hospital after overdosing at a party. As Dexter walks out behind him, Deb says, accusingly, "He could have died. You call yourself his father? You didn't even know where the fuck he was. Look at what you've done to him. This is all your fault!"
Dexter visits Dr. Salena Patel, a veterinarian, to obtain syringes and ketamine under false pretenses. He ignores Deb when she says, "Don’t."
As Dexter waits in his truck outside Jasper Hodge's house, Deb tells him to walk away, go home to Harrison, and work on being a good day. Dexter angrily replies, "Harrison almost died because of this guy. He doesn't get to just walk away. And I am a good dad!" Deb says, "I haven't seen you like this before. This isn't about the Code or feeding your urges. This is vengeance." Dexter quips, "Yup."
Dexter finds the job application that Kurt gave Harrison. While Deb doesn"t view it as a problem, Dexter thinks that his son working for the father of his last victim is pretty dire. Deb asks, "And that's the fucking problem, right? No one can live with a motherfucking psycho who's addicted to murder." She slaps her head. Harrison comes inside and thanks Dexter for the place to stay. They talk about the job and Dexter expresses his doubts about Kurt. Harrison asks for his signature on the job application but Dexter tells him no. Harrison informs him that he didn"t go to therapy the night before but talked to Kurt, so Dexter should be thanking Kurt.
Together, Dexter and Harrison attend a therapy session. They discuss Harrison's trouble at school, his overdose, and lack of communication. As Harrison begins to explain why it hasn’t been easy being "Jim’s" son, Deb warns Dexter to brace himself. Harrison opens up about his past and the therapist thanks him for his honesty. To Dexter, Deb says, "The problem is the only people you're ever honest with, you end up killing." When Dexter is asked to talk about his childhood, Deb asks, "Where to begin, Dex? The fact that you're talking to your dead sister right now in this room? Or your mother being chopped up in front of you? Or your adoptive cop dad teaching you to be a serial killer? You should talk. They're waiting for you." The session ends with Harrison feeling abandoned.
Angela, upset that Harrison spent the night with her daughter, drives him home. She orders Dexter to handle the situation. Deb says, "We can only hope that they used protection. 'Cause there's one thing I guaran-fucking-do-know and that is that you are not ready to be a grandfather." Dexter quips, "At least I don't have to have the sex talk with him," with Deb replying, "God, that would've been awful." She advises Dexter to let things settle down with Harrison and to take care of the Molly situation.
Deb warns Dexter that Harrison is drifting further and further toward Kurt Caldwell and he should kill Kurt. Dexter, though, doesn't agree. "If I kill Kurt, that's just another secret. Kurt suddenly disappears, Harrison is crushed. He never finds out who Kurt really was. The kid has already had too many losses. One more could just push us further apart. Angela's already gunning for Kurt. She's building a case. Once she arrests him, it's all over. Harrison will see who Kurt really is. In the meantime, I'll make sure Harrison is safe." Deb sarcastically replies, "Yeah. Good call. Leave it to the police to handle. What could possibly go wrong?"
- Dexter's Cabin
- Debra Morgan (when alive)
- Dexter Morgan/New Blood
- Iron Lake High School
- Jim Lindsay (Dexter's alias)
- Iron Lake
- According to Clyde Philips in an interview with Variety, “The Deb character plays his conscience — that part of your brain, however big or small it might be, that’s that question mark in your head that’s always there.”