Dexter visits Hannah in jail to explain why he didn't protect her and she in turn explains why she did what she did. She seems to understand Dexter but has her own plans which don't include prison. Captain LaGuerta disregards the evidence she and Tom Matthews have discovered - and which Dexter planted - which points to Sgt. Doakes as the Bay Harbor Butcher and continues her investigation into Dexter. She arrests him but Dexter has set her up and she is forced to release him leading most at Miami Metro to believe she was trying to frame him. Dexter still wants to get rid of the man who killed his mother but comes to the realization that he will have to deal with LaGuerta even if eliminating her falls outside his code.
Dexter meets Hannah in the prison and she admits that she tried to kill Debra. Dexter and Hannah are in love with each other, but they do not trust in each other. Hannah calls Arlene and asks her something. LaGuerta arrests Dexter at home, but the evidence was planted by Dexter as part of a scheme to discredit her. Hannah goes to the court and he does not feel well and is sent to the emergency of a hospital; then she flees. LaGuerta summons Debra and shows a DVD that Mike Anderson has collected in a gas station showing her buying gas. Dexter finds Estrada and Debra tells him the findings of the Captain. Angel gives a New Year party in his restaurant and Debra notes that neither LaGuerta nor Dexter are there. She goes to the container where Dexter is forging a crime scene showing that LaGuerta and Estrada killed each other. Debra has a surprising attitude.
Dexter must protect himself when LaGuerta closes in on his secret.
- Open with Hannah in jail. Dexter comes to visit her. She's furious with him and says she poisoned Debra because "she was trying to keep us apart." Dexter says she left him no choice. She says his secret is safe with her. He tells her if there were any other way to keep Debra safe he would have found it. Dexter is emotional and tells Hannah he misses her. She suggests they could leave the country together but Dexter says they'll never be able to trust one another. They begin making out and she bites him.
Hannah calls Arlene from prison and she needs her help.
Harrison asks about Hannah. There is a knock on Dexter's door. It's Maria, there with several officers. She places him under arrest for the murder of Estrada and reads him his rights.
Dexter is brought into the station in cuffs. Maria tells Angel she has proof Dexter is the Bay Harbor Butcher. Debra tries to intervene but Maria tells her to stand down.
Dexter's official statement is that he went fishing the night before. Maria accuses him of cutting Estrada's body into pieces and dumping him in the ocean. She has cell phone pictures of him with plastic bags and says one of them contained Estrada's bloody shirt and wallet. Maria accuses him of betraying everybody in the station. Dexter accuses her of being blinded by her relationship with Doakes. Masuka comes into the room and says the shirt was from his arrest 30 years earlier and the wallet has Maria's print on it. Maria thinks Dexter has set her up. Dexter is allowed to leave.
Maria and Dexter end up in the elevator together. Maria said Doakes "always knew there was something wrong with you."
Dexter flashes back to working with Doakes on a case. Maria calls Doakes away and Dexter sees her give him a key. This seems to disappoint Doakes.
Angel has figured out that Maria was behind Estrada's release. He tells her if she wants to keep her job she needs to back off Dexter.
Debra drops by Dexter's place. Dexter tells her that his plan worked and Maria shouldn't be able to come at him anymore. Dexter thinks it was either her or him. Debra asks about Hannah and the potential for her using what she knows about him to get a reduced sentence at her arraignment the following day. Dexter doesn't think she will because she's in love with him. Harry shows up and reminds Dexter that Estrada is still out there. If Maria finds him she'll probably offer him a deal.
Dexter shows up at the last known address of Estrada's wife. She says she hasn't seen him in years. But she is still wearing her wedding ring.
Back in a flashback Dexter is a little too excited to reenact a crime scene for Doakes' tastes.
Dexter follows Estrada's wife from her apartment complex.
Maria asks Matthews for his support. He eventually agrees to help her in some way.
Debra shows up for Hannah's arraignment. Before it begins Debra asks Hannah to confess. Hannah reminds her that Debra knows what Dexter is and asks how she justifies not arresting her brother. Hannah is denied bail. On her way out of the courtroom Arlene slips her something.
Angel asks Maria to show up at his retirement party. He thinks it will be an opportunity for her to apologize to Dexter and smooth things over.
On her ride back to the prison Hannah begins having seizures. She is rushed to the hospital and begins receiving treatment.
Maria calls Debra into her office. She says she allowed her feelings for Doakes to impact her decision-making and apologizes. Maria wants to go over some loose ends on Travis Marshall's death. Debra says she didn't go the church that day. She pops in footage from a gas station two blocks from the church that shows Debra was in the area 20 minutes before the fire. Maria wonders why she was filling up a gas can and not her car. She asks if there anything Debra would like to get off her chest. Maria says she thinks Debra made a mistake trying to protect Dexter. Maria says this is only the start of "a much larger conversation."
Dexter follows Estrada's wife to a park. She's been bringing him food. After she leaves Dexter pays some kids to throw a ball at him and lead him to Dexter's car. He knocks him out and throws him into the back of his car. Debra calls Dexter.
Hannah begins to wake up at the hospital.
After hearing the latest from Maria, Dexter tells Debra "this is bad." Dexter wants to figure out what else Maria does or doesn't know.
Hannah has disappeared from her hospital bed.
Dexter breaks into Maria's place. He finds warrants for Maria to track the GPS signals on Dexter and Maria's phones. This will allow her to prove that Debra was his accomplice. Harry thinks Dexter should run, but he says he can't do it at this point. He wants to stand his ground. He appears to be considering killing Maria. Harry reminds him that Maria doesn't meet the code, but Dexter says he simply can't let Debra go down for his crimes.
Dexter flashes to an angry Doakes telling Dexter that he should have never gotten involved with Maria. Something Dexter said is verbatim to what Doakes read in the journal of a guy he is trying to arrest for murder. Doakes thinks there is something wrong with Dexter.
Dexter has Estrada call Maria and tell her to meet him at the same container. Estrada tells Dexter that his mother was a snitch and "it was her or me." Dexter tells Estrada he has another kill coming up that won't be easy. Dexter says that tonight he'll be an ordinary killer.
Angel's party is in full swing. Debra is trying to get in touch with Dexter. Jamie sits down at a table with Quinn, who is getting drunk to forget his troubles. Debra calls the station and finds out Maria is headed to the shipping yards.
Hannah leaves a plant in front of Dexter's door.
Maria arrives at the container. She enters with gun drawn and finds Estrada's body. Dexter sneaks up from behind and gets a needle in her neck. His plan is to make it look as if Maria and Estrada killed one another.
Another car arrives at the container. It is Debra. She hears a gun shot and walks in. She points her gun at Dexter and says she can't let him go through with it. Maria wakes up and tells Debra to shoot Dexter. Maria tells Debra that she's a good person. Dexter agrees and, disarming himself, tells Debra to "do what you gotta do", ready to be killed. Debra instead shoots and kills Maria, then rushes to her side, hugs her and cries.
Dexter and Debra go to Angel's party. Dexter's voiceover talks about the fallout of breaking rules. "Is this the beginning of the end?"