After an unspectacular season 3 marred by muddled plotting, pointless B-stories, and Jimmy Smits redefining the art of scenery chewing, Showtime’s venerable “Serial Killer With a Heart of Gold” drama Dexter returned a changed show brimming with suspense, character evolution, and the most horrifying villain ever to menace the small screen. Those B-stories though? Still hecka pointless.

Season 4 found Dexter uncomfortably adjusting to life in the suburbs with a wife & baby. Dating sweet single mom Rita may have started out as just a cover story to mask Dex’s nighttime hobby, but family life started to feel right for the self proclaimed soulless monster. Campouts and extra-nosy neighborhood watch folk made for some amusing stealth scenarios, but the heart of Dexter’s study in family life would come from a surprising and sinister mentor.

Enter John Lithgow as the Trinity Killer, a terrifyingly prolific murderer whose expertly crafted backstory was made even better in a series of tantalizing one piece at a time reveals. The season took delight in building, peaking, and unraveling a dynamic portrait of a man sick and damaged enough to constantly reenact his childhood through the death of strangers yet self aware and canny enough to build a near perfect social artifice. And the depictions of his ritualistic cycle of kills would be enough to haunt and sicken even a jaded veteran of Creative Serial Killer Theater (that means you, Silence of the Lambs and CSI).