The episode begins with Hannah’s cruising around the ladies jail to meet Dexter for a visit. Hannah asks why he turned her in when he said he loved her. He says she poisoned Deb. Hannah seems to admit it and says “because she tried to keep us apart”. Hannah tells him she’ll be behind bars forever. She says he should have chosen her. Dexter reminds her that Deb’s his sister. Dexter tells her if there was any other way to keep Deb safe, he would have done it. He’s clearly distraught and tells her he misses her a lot. She tells him it’s not too late that if the pen disappears, she can be free. She says they can run away together.
Dexter tells her he can never trust her and she can never trust him. He says they knew it would come to this; one of them dead or behind bars. Dexter says he’s sorry. He kisses her passionately and she bites his tongue hard enough to stop him; hard enough to draw blood. He pulls away shocked and Hannah says good-bye. Arlene gets a collect call from jail; it’s Hannah. She tells her she needs help, that she can’t stay behind bars. She reminds Arlene that she owes her for taking out the counselor who was abusing her. Arlene says to tell her what to do. Dexter’s playing with Harrison. There’s a knock at the door. It’s La Guerta. She says it’s best if Harrison is in another room. La Guerta arrests him for the murder of Hector Estrada. Dexter is visibly shocked. La Guerta hauls him in to the station. Everyone stares and is shocked. Angel wants to know why she’s cuffed Dexter.
She says she has evidence that he’s the Bay Harbor Butcher. Angel says it’s Doakes. Deb and Angel both confront her, but she refuses to back down. Angel tells Deb he’s on it. La Guerta has Dexter in interrogation. She asks where he was last night and he said he was fishing and then went home to play with Harrison. Angel tells La Guerta that she’s got nothing. La Guerta has photos of Dexter carrying bags of something out to his boat. La Guerta accuses him of framing Doakes. She says she’s going to nail him to the wall. Vince comes in to tell her that the shirt did have Hector Estrada’s blood on it but it also had an evidence tag. It was the shirt he wore when he was booked in 1973. They also found his wallet and it had her fingerprint on it. She has to cut him loose.
La Guerta ends up in the elevator with Dexter and accuses him of setting her up. Angel chases down La Guerta and confronts her about pushing to let Hector Estrada out on parole soon. He tells her everybody thinks she’s framing Dexter and that she needs to drop it before she loses her job. Angel tells her she can work her way out of it, but she needs to let it go. At Dexter’s Deb tells him Hannah’s, being arraigned tomorrow and she could spill the beans on him to work a better deal. Dexter says she won’t because she’s in love with him. Next day, Dexter shows up at Hector’s wife’s house. He tells her that he’s Hector’s parole officer. She says she hasn’t seen him in years.
There’s a guy inside the apartment yelling for her, but she says it’s not him. Dexter wants to know why they’re still married and she says she’s Catholic. Flashback and Doakes and Dexter are working a case on a boat. Doakes asks him to explain it and Dexter acts out the crime based on the spatter. Back to the present and Dexter’s outside the wife’s house and sees her sneak out of the apartment. She gets in her car and takes off; Dexter follows. La Guerta’s in her office and Matthews comes in to see her. At Hannah’s arraignment, Deb’s there since she’s the arresting officer. Hannah asks how her wrist is and she says she’s getting better. Deb says she should save time and trouble and confess. Hannah says her conscience is clear. Hannah asks her how she justifies arresting her and not Dexter.
Hannah’s denied bail and Arlene’s there and starts crying. She rushes to hug Hannah and slips her something. Angel comes in to check on La Guerta. He says she needs to come to his party and that she should apologize to Dexter in public. Hannah’s in the back of the prison transport van and starts convulsing. They rush in to check on her and then divert to the hospital. Hannah’s at the hospital, zip tied to the bed and really out of it. Estrada’s wife stops at a park and Dexter follows. She’s carrying some bags. La Guerta calls Deb in and says she was right. She tells Deb that she was right and she let her feelings for Doakes get in the way. She says what she did to Dexter was negligent and unforgivable. She says she’ll probably be suspended or worse.
La Guerta says in case she’s not going to be there, she needs to close up some loose ends. She pulls out the file on Travis Marshall. She says she needs to clear up the timeline. She asks Deb if she was ever at the church where he died. La Guerta pulls out an envelope and she says Sgt Mike Anderson’s wife sent her some video footage he had ordered of gas stations near the church. She’s got video of Deb pumping gas at the gas station that was the gas that flamed up the church. She’s seen pumping into a gas can. La Guerta wants to know why she was pumping gas into a gas can. She wants to know why she lied about being near the church. La Guerta asks Deb if there’s something she wants to get off her chest and Deb says yes. She tells La Guerta that she’s been under a lot of stress.
La Guerta says “You know what I think?” She says she’s not the only person who made a mistake trying to protect someone she cared about. In the park, Dexter sees Estrada and his wife. She’s brought him a gun and some other essentials. Hector lounges in the sun. Dexter’s pays off some kids to throw a ball at Hector. He chases them out of the park; Dex on the way puts a shot in his neck and tosses him in his trunk. He gets an urgent call from Deb and says to give him 15. At the hospital, they think Hannah’s catatonic, but she’s wiggling her fingers. Deb tells Dexter about her conversation with La Guerta. He tells her he’ll fix it. He tells her to go back to work and act normal. At the hospital, Hannah’s gone. Dexter’s at La Guerta’s and Harry’s keeping him company. He asks what he’s hoping to find and he says he doesn’t know.
He finds warrants to track the GPS on his and Deb’s phones the night of Travis Marshall’s murder. Dex realizes instantly that this will tie both him and Deb to his death. La Guerta gets a call from Hector Estrada. He tells her he’s back at the shopping yard in the same container. He asks Dexter if he’ll let him go now. Dex says no and asks if he thinks he can be a killer and not a liar. Dex pulls out a knife and Hector apologizes for having his mother killed. He says his mother was a snitch and it was her or him. He says it was 40 years ago and asks why they’re still talking about it. Dexter asks if it made him feel bad. Hector said it was her or him. Dexter tells him killing him will be easy, but he’s got another kill that will not be so easy. Hector says that’s why he had to kill his mother too; survival.
Deb shows up at Angel’s party and asks Jamie if she’s seen Dexter. Jamie says he’s not there and that Harrison conked out. Deb asks Angel if she’s seen Dexter or La Guerta and he says no. She calls into dispatch for information on La Guerta’s car and is told she’s at the shipping yard. Deb calls Dexter and gets no answer. She leaves a message for him not to do what he’s thinking about doing and runs out. Hannah shows up at Dexter’s place and leaves a plant. At the shipping yard, La Guerta gets out into the foggy night, gun drawn. She comes into the freight car and finds a dead Hector. Dexter gives her, a paralytic shot to the neck and goes to work. Turns out, he’s not planning to kill her; he’s going to set her up. He’s going to use her gun to shoot through the stab wound in Hector’s stomach and then use Hector’s gun to shoot La Guerta.
Deb shows up at the scene and hears a gun shot. Deb comes in to the freight car. She pulls the gun on him. He tells her she shouldn’t be there. She asks him what he’s doing and he says he’s doing what needs to be done. Deb cries and tells him she can’t let him do it. La Guerta comes too and tells Deb to kill Dexter. She tells her to shoot him. La Guerta says, this is not who you are. She says she’s a good person and not like him. Dexter tells her that everything La Guerta says is true and that she is a good person.
He drops the knife and spreads his arms and tells her do what she’s got to do. In the end she shoots La Guerta. Then she takes her in her arms and sobs as she holds her body. Dexter is stunned. It’s New Years at Angel’s club. Deb and Dexter walk into the party together.