Last week’s episode ended with a cliffhanger. The character played by Julia Stiles finally appeared, a bruised and battered girl, who witnessed Dexter killing Boyd Fowler. This week’s episode opens with a tender side of Dexter showing, cleaning up her wounds. Harry appears, telling him to go home and take care of his son.
The girl fights Dexter, so he administers a tranquilizer. Deb calls and begs for his help on the decapitation case from their informant. Dexter realizes that he has been out all night, as has Deb, so the nanny has been with Harrison all night. She quits. Dexter wants to go back in to the office, so that he can identify the girl. He put her fingerprints on an empty water bottle so that he can identify her.
Quinn knows that Kyle Butler is Dexter. He wants to prove it by having Arthur Mitchell’s family ID a photograph, but refuses to let the FBI have the photograph. He manages to follow the FBI officer in charge, and locates the safehouse so that he can go back and ask them to identify the photo.
Dexter uses Harrison as a distraction at the office. Everyone is playing with the baby, so he can go identify the girl. She has no record, so he prints off the information about Lumen Ann Pierce from Minnesota, and takes off. Quinn, of course, is suspicious, but can’t find out anything when he tries to spy on Dexter’s computer.
Dexter steals some of Masuka’s antibiotics so that he can help the mystery girl heal. When she awakens, she rfuses to take them, and tells him her name is Rachel. She asks him to let her go, but he refuses, because she saw him at the house. He assures her that she is in a safe place and that he isn’t going to hurt her, though he locks her in the building.
LaGuerta makes Batista go to the hospital to apologize to Lopez, hoping that he will drop the charges and the IA investigation. He agrees to drop the charges, but doesn’t seem to really want to accept the apology. And IA isn’t going to let it go.
Dexter tracks down Lumen’s belongings at the hotel she had checked into, because the account had gone to collections. He poses as her husband to pick up her luggage, and pays off her bill. All he finds out is that she left her family, due to something her father had done, because of a letter written to her by her mother. He leaves her belongings and the letter in her locked room.
Dexter begs the nanny to return. Masuka figures out someone has been pilfering his meds. IA begins harassing LaGuerta.
Masuka has identified a fingerprint from the crime scene, and they are chasing after Carlos and Marco Fuentes. Debra botches the raid when a hostage almost dies and the suspects get away. Meanwhile, Quinn is stalking the Mitchell family.
Dexter finds himself on a brand new kind of hunt. Lumen beats him over the head when he returns, and manages to run out of captivity. She closes the door and locks it behind her, but he is able to bust out. When he catches up to her, she is trying to get away, but is scared off by a car full of boys. Obviously, something traumatic happened to her, long before she ever met Boyd. Harry keeps hinting that perhaps Dexter needs to get rid of her. Instead, he takes her out to Boyd’s dumping ground, to show her what her fate could have been had he not killed Boyd. He is seeking her trust. He tells her about Rita. He gives her his knife as a symbol of trust. She stabs at him, and when he doesn’t attack her, she breaks down.
Quinn has been arrested for approaching Jonah Mitchell to see if Kyle Butler is really Dexter Morgan. LaGuerta gets pissed off and puts him on suspension, because terminating him would bring about a hearing. Quinn believes Jonah recognized Dexter. Debra wants to go home with Quinn.
Lumen cleans up Dexter’s arm and confides in him that Boyd was not the first person to do this to her. There is a whole group. And she wants revenge. Welcome to a new sort of nemesis, Dexter Morgan!
Previews for next week’s show have a bossy Lumen telling Dexter that he cannot tell her what to do, and her naively stalking her prey. Harry fears that her carelessness will bring Dexter down. Could it be? Will this be the season that he gets caught? Or is he going to do the same as in season 3, and create and kill his own monster creation?