In the sixth-season premiere, Dexter shows up at his 20th high-school reunion with the intention of confronting the former prom king. Elsewhere, an investigation into a heinous murder with religious overtones leads Dexter to ponder spiritual matters and wonder about his son's legacy. And an unexpected situation results in Debra becoming a hero.
Brother Sam, a minister with a criminal history, is brought in by the homicide department to help solve a macabre murder, but Dexter sees him for what he really is—and it's definitely not a man of God. Elsewhere, Debra's sudden hero status elicits a pair of surprising proposals.
Gellar and Travis' latest disturbing tableau has Dexter questioning matters of faith. Meanwhile, Homicide uncovers evidence that the killings are religion-motivated and tries to find the zealot responsible; Debra gives her first official press briefing.
Dexter receives spiritual guidance from his new friend, Brother Sam, while his search for the Doomsday Killers leads him in a new direction. Later, Quinn and Batista visit Prof. Gellar's former university; and Debra is required to undergo post-shooting therapy.
Dexter receives help from an unexpected source while hunting for the Doomsday Killers and trying to stay a step ahead of the Homicide Division. Meanwhile, Debra's visits to her therapist uncover something surprising.
Dexter develops a macabre scheme to try to apprehend the Doomsday Killers. Meanwhile, Debra and LaGuerta's battle over the case of the dead call girl intensifies and Debra's therapist makes a bold and disturbing suggestion.