The story is further complicated by the fact that Sgt Doakes himself has set a goal to find out what is wrong with Dexter. He shadowed in every free minute, which significantly restricts freedom of movement Dexter. In addition, he is limited by his sister, who moves in with him. Debra is looking at him protection and security, as it has been happening in the first season of all only as the girlfriend of the Kühllasterkillers is considered.
Paul, Rita's violent husband, because Dexter is back in jail, asks Rita for evidence of his innocence to search, which refuses this - shortly after he dies in a jail brawl. Rita finds the evidence sought by Paul and realizes that Paul was breach of his parole - Paul with a drug syringe found in the arm - directed by Dexter was. She confronts him and wants to know is where he got the drugs. Dissatisfied with his answer, she thinks of now, Dexter is a drug addict, forcing him to go to a support group for addicts.
Dexter meets Lila know where that is after a short time his Suchtbetreuerin. She encouraged him to rely more on his instincts and his conscience, not knowing that Dexter has neither. (The assessment is based primarily on how Dexter sees himself. But it is clear that he does have feelings for other people, including his half-sister and his girlfriend Rita and their children. This is shown whenever these in distress and lead Dexter advised to impulsive, irrational behavior, such as the precipitation of Rita's ex-husband or the "refrigerated lorry-Killer", which his brother was.) Dexter does with this experiment, but is soon discovered that he makes mistakes to bring the Agent Lundy and Sgt Doakes on the right track.
While Dexter and Lila get closer, the relationship with Rita suffers under it, until its failure. When Dexter realizes how important he is Rita and their children, he tries to keep in contact with them. Lila becomes jealous and shows her true colors.
To run Lundy's investigation into the void, Dexter writes a manifesto, which sends it to the Miami Tribune, on behalf of the Bay Harbor Butcher. But the shot backfires: Lundy recognizes the purpose of the document and speculates that the serial killer himself works with the police.
As Sgt Doakes, who was suspended because of a attack on Dexter on duty, accidentally discovers that a butcher victim was acquitted due Blutspurenanlyse Dexter, he is convinced of his guilt. He searched his apartment and finds Dexter's murder trophies: slides with blood samples of all the victims. Doakes it assumes itself to be analyzed it. Then he in turn is suspected to have anything to do with the murders, he himself is wanted by Lundy people. Man finally finds his car and to the slide. Doakes is now the main suspect, and Dexter tries to use that phrase to pull your head out of the loop. Doakes confronts Dexter with the evidence in a remote hut drug trade. Although wounded, Dexter locks him in a cage and leaves him at first. Dexter begins to spread false evidence, indicate on Doakes as the killer. Only his former partner LaGuerta believes in his innocence and tried to find evidence. When she turns to Lundy, however, rejects this further investigation, as they previously held back evidence, although it's innocence Doakes' considering.
Dexter finds out that his foster father Harry an affair with his natural mother and had killed himself when he realized what the monster he had created with Dexter. Burned out by the events and revelations will, put his life as a serial killer Dexter to an end and take farewell preparations. At his last dinner with Debra, but he knows how important he is for his sister. He decides to showcase his original plan, Doakes as the Bay Harbour Butcher to pursue.
Lila is still looking for Dexter and Doakes finds so and another victim in the dealer hut. It breaks the cabin with propane gas and thus prevents that Dexter is exposed as a killer. Lila now expects that he loves her again, as it now knows his dark secret. It surprised him, however, in how he is preparing for her death and wants revenge, therefore, to Rita and the children. Dexter, however, this can prevent just yet. He follows Lila to Paris, where he kills them.
