Season 7 returns in explosive fashion, as Dexter is finally forced to confront his greatest fear, as Debra witnesses his insatiable, ritualistic slaying of a killer. Now Deb knows the secret of his Dark Passenger, his undeniable thirst for blood, and the Code that their father Harry instilled in him as a young boy. But as Deb tries to reconcile the unfathomable idea that her beloved, mild-mannered brother is Miami’s most notorious serial killer, Dexter is still pulled by his natural impulses to seek out the guilty and exact his brand of vigilante justice, which leads him on the trail of a brutal Ukrainian mobster.
Along the way, Dexter meets Hannah McKay, a strong, independent woman with a past that she's struggled to put behind her. As a turn of events leads Miami Metro Homicide to ask for her help in solving some old cases, Dexter works with her and begins to wonder if there's more to this woman than she's professed.