Greene wants to impress the police force, especially Dexter, and is revealed to have acquired the prosthetic hand from the Ice Truck Killer case, which he mails to Dexter.Debra refuses to yield to pressure to close the case of the overdose death of a prostitute, eventually discovering that Deputy Chief Matthews was present when the woman died.
The season follows Dexter's and Miami Metro's investigations into a string of bizarre ritualistic killings featuring overtly religious apocalyptic symbolism.On November 18, 2011, it was announced that Dexter had been renewed for two more seasons.He takes Travis back to the church where Travis carried out his earlier murders, which Dexter has set up as a kill room.The season's subplots include Angel's sister dating Louis Greene.Batista thinks he was passed over due to the feud between Matthews and La Guerta.
La Guerta continuously thwarts Debra's attempts to make a good first impression as the new lieutenant by giving her the wrong advice; however, Debra makes an independent decision to hire Mike Anderson as her replacement, against La Guerta's recommendation.
Shortly after, Quinn learns of Deb's promotion and surmises that it was her reason for ending their relationship.
Quinn begins a long pattern of barhopping, drunkenness, and one-night stands; his unprofessional behavior angers and ultimately endangers Batista, his new partner.
Masuka eventually fires Ryan when she steals a painted prosthetic hand from the Ice Truck Killer crime scenes, which shows up on an internet auction site.
Masuka quickly hires another intern, video game designer and computer programmer Louis Greene, to fix the problem.
Matthews is forced to retire after La Guerta leaks the information.