There is another victim of the phantom arsonist, the fifth in two weeks. Dexter thinks has a pretty good idea who is behind it. He is frustrated because he promised Deb not to interfere in police cases. He tries to explain his dark passenger to Hannah but they're interrupted by a man peeking through the window - who turns out to be Hannah's father who has just been released from prison. He wasn't a very good father - he once left her alone in a motel room for three days while he went off to play poker. He seems to have reformed but after she refuses him a loan he turns particularly nasty. Dexter knows how to make things right. Captain LaGuerta tells her old boss, Tom Matthews, that she suspects Dexter is the Bay Harbor Butcher. When he tells her the Ice Truck Killer was Dexter's brother, she knows she's right, even though Matthews disagrees. Quinn goes after Nadia's boss, George Novikov, when he decides to send her out of State to work in another club.
Miami has a new serial-killer that burns his victims to death and is called the Phantom arsonist by the media and the police. Dexter suspects of the Fire Inspector Phil Bosso, but her promises Debra not to interfere in the police investigation. Dexter and Hannah have a conversation about his urge to kill when they are surprised by Hannah's father Clint McKay that has just left prison and tells that he would like to apologize to Hannah for being a bad father. But he asks for a loan and when Hannah tells that she does not have the money, he turns into a disgusting creature. Dexter finds that Bosso is not a criminal since Masuka finds a clue of the Phantom in the security footage of the bus burnt by him. LaGuerta makes a deal with Matthew to help her to investigate the Bay Harbor Butcher that she believes is Dexter. Quinn learns that George will send Nadia to Dubai and he goes to the club and kills the mobster; then he forges the crime scene. Dexter finds the Phantom but he leaves the arsonist for Angel and Debra. Clint blackmails Hannah and Dexter and he learns that her father was the one that tipped Sal with information about Hannah. Dexter brings Clint to a boat ride with no return.
The Phantom Arsonist continues his spree across Miami.
- The police are investigating the scene of the fifth arson attack in five weeks, this time a six-year old and his mother. Witnesses claim the suspect was enormous. The same accelerant was used and the word "Bobby" was again scrawled into a wall. Dexter is suspicious of the arson investigator, Phil Bosso (Brett Rickaby).
Dexter tells Hannah about "The Phantom" arsonist, and admits being frustrated he's promised Debra he wouldn't take any cases from the police. He tells her about feeling like the "Dark Passenger" doesn't give him a choice. Hannah doesn't seem to understand.
Her father, Clint (Jim Beaver), shows up unexpectedly. Hannah hasn't seen him since he went to prison for writing bad checks. After sessions with the prison psychiatrist he feels the need to apologize to Hannah and tell that he always loved her. He has brought her a dollhouse from her childhood. Hannah doesn't look happy and after he leaves she tells Dexter he couldn't have brought a worse gift. She says he bought her the dollhouse after leaving her alone for three days to play in a poker tournament.
Bosso briefs Miami Metro about the likely suspect. Dexter thinks it sounds a lot like Bosso. It doesn't seem like there are any other leads. Hannah sends Dexter a text that she's meeting her father. The rest of the department is finding out about Dexter's relationship with Hannah.
Debra asks Dexter whether it's safe for him to be dating somebody so notorious when he needs to lay low. She tells him she's not going to stop investigating Hannah. Debra, meanwhile, is taking medication for anxiety.
Dexter looks into Bosso and grows even more suspicious. He follows him from the station to a Civil War reenactment and learns that he has an alibi for the most recent fire. Boss isn't "The Phantom." Hannah asks Dexter to join her for dinner with Clint.
At dinner Hannah and Clint seems to be getting along splendidly. They are planning to spend the night together, with Dexter saying he'll bring them breakfast the next morning.
A shady-looking character boards a public bus, a young man whose face is obscured by the bill of a baseball cap. He puts on a fire retardant suit and begins hosing people down with an accelerant. A huge fire breaks out in the rear of the bus.
The next morning Clint and Hannah still seem to be doing fantastically well. He talks about needing to raise $20,000 for a crawfish shipping business. When she says no he gets very angry. He goes for a drive and Dexter tells her she's doing the right thing. Hannah isn't sure and this leads to an argument about the "Dark Passenger." Dexter gets a text about the Phantom's latest crime scene.
A female witness (Jenny Phagan) and a male witness (Mike Polli) had varying discriptions of the arsonist killer, but both agree that he was very tall.
This time the Phantom has written "It's Bobby" on a bus window. Dexter tells a suspicious Debra about vetting Bosso and she's upset he put himself in a dangerous situation. A very upset Hannah calls Dexter.
Dexter arrives at Hannah's to find that a drunken Clint has driven his truck through her green house. Clint begins to yell at her, saying she is responsible for the death of her mother. Dexter demands that he leave as Hannah sobs. Dexter doesn't know how to help Hannah emotionally.
Maria LaGuerta (Luna Lauren Velez) meets with Tom Matthews (Geoff Pierson). In her opinion, the only suspicious Miami PD employee remaining seems to be Dexter. Matthews thinks she should look into Doakes' final days, as the real Bay Harbor Butcher probably killed him.
Hannah tells Dexter she feels like Clint suckered her into thinking he was a good person. She says she hopes he's gone for good and remarks how scary Dexter sounded when he told Clint to get lost.
Vince Masuka (C.S. Lee) has analyzed security footage from the bus. They can't see the murderous arsonist's face, but notices that he grabs a pole with his bare hand.
Quinn (Desmond Harrington) gets a call from Nadia (Katia Winter) that she's being shipped off to a sex club in Dubai. Angel joins him on a trip to the club where Quinn barges past bouncer Mike (Brent Chase) at the front door and storms into the back room. George Novikov (Jason Gedrick) pulls a pistol on Quinn, then sets it aside and starts slapping Nadia around. Quinn shoots him dead. Quinn has Nadia help him make it look like George shot him in the arm first. Quinn tells her to grab money from the safe and leave.
There is no match for the Phantom's print. Debra and Dexter focus on the meaning of "Bobby."
Dexter sneaks a copy of the Phantom's fingerprint on a thumb drive and trots off on an unofficial visit to the juvenile records office. He breaks into the office over lunch hour and runs the print. It matches the name of Joseph Jensen, who burned down his school's gym at age 12 and was just released from a psychiatric hospital a month ago. Dexter tells Harry he doesn't think he can control himself. Harry and Dexter discuss the possibility that his Dark Passenger isn't real.
LaGuerta and Matthews visit Juan Alonzo (Wayne Lopez), the man who owned the property where Doakes had been staying. He tells them he never knowingly rented to Doakes, instead to a man named Santos Jimenez who he later found out was connected to Columbian drug dealers. Matthews recognizes the name Jimenez.
Matthews tells LaGuerta that Jimenez was one of the three men responsible for killing Dexter's mother. He also tells her that the Ice Truck Killer was Dexter's brother. They wonder if perhaps Doakes was onto Dexter, which would give him motive. Matthews thinks he's the one who should talk to Dexter.
Clint drops by Dexter's place unannounced. He says that he has evidence Hannah killed a counselor at a halfway house. Clint knows of a roommate who witnessed her poison the counselor. If Dexter doesn't give him money, he'll turn in Hannah. It also turns out that Clint was selling the crime writer Price information about Hannah for his books. The real reason he needs the money is that he has significant gambling debt. Dexter tells him to leave, with Clint dropping the name Arlene on his way out.
Based on the timeline of the two shots, Angel demands the truth from Quinn. Quinn sticks to his lie with a semi-plausible scenario.
Dexter tells Hannah about the conversation with Clint. She confirms that Arlene is the only person who can put her in jail. Hannah says she can't kill her own father and goes to call her bank. Dexter tells Harry that Clint doesn't meet the code.
Dexter pays Joseph Jensen (Mike Foy) a visit at his home. After knocking Jensen out he tapes him to the slab. When he comes to Jensen tells him Bobby was his best friend when he was young. He took the blame for a fire Bobby set and he blames him for getting send to the "nut house." He says Bobby is the reason he's been killing people. Dexter positions the knife above Jensen's chest, then pauses, making a connection to his own past history.
Debra and Angel arrive at Jensen's place because of an anonymous tip. He's lying on the floor unconscious, but still alive.
Dexter meets Clint in an underground parking garage. He knocks him out with his traditional syringe to the neck and takes him on his boat. Dexter tells Clint that even though he doesn't meet his code he "wants to" kill him. Dexter stabs him in the chest and throws his weighted body overboard.
Debra calls Dexter about finding Jensen. She knows it was him and thanks her brother for refraining from killing Jensen and letting the police finish up the case. He asks her to lay off Hannah, but she refuses.
Dexter tells Hannah he had "a talk" with Clint and he won't be bothering her again. She hugs him and thanks him. He tells her his Dark Passenger doesn't exist and thinks she might understand him better than he understands himself. She says she loves him and he reciprocates.
Debra tells Angel they need to look for a woman named Arlene, a name Clint left in a message to Debra the previous night, saying she was a witness to a murder.