The promo for this episode shows that Brian Moser (The Ice Truck Killer) has appeared as Dexter's Dark Passenger. It also shows that Trinity's family is/was living in Nebraska and that Sally (wife/mother) and Rebecca (daughter) Mitchell have been murdered in the same style of the Trinity killing cycle. Sally appears to have suffered a massive head wound, and Rebecca bled out in the bathtub.
Dexter is caught up in a very personal case that once again awakens the needs of his Dark Passenger; Debra feels overwhelmed by her new Lieutenant duties, made all the more complicated when she finds out Quinn slept with a witness in the Doomsday case.
Dexter disposes of Nick's body with the assistance of his brother Brian now currently serving as Dexter's conscience telling him to embrace his Dark Passenger. Dexter gets a call from Debra telling him to come back at the station for something urgent. Back at the station, Debra tells Dexter that the "Trinity Killer" has killed again, the latest victims being his own wife Sally who was bludgeoned to death and his daughter Rebecca who was killed in a similar manner to the bathtub murders. Jonah was the only survivor from the attack and since Dexter had already killed the real "Trinity", Jonah seems to be the likely suspect. Dexter gets suspicious of Jonah and goes to Nebraska with the intention of killing him, but ends up not doing so.
- Michael C. Hall: Dexter Morgan
- Jennifer Carpenter: Debra Morgan
- Desmond Harrington: Joey Quinn
- C.S. Lee: Vince Masuka
- Lauren Vélez: Maria LaGuerta
- David Zayas: Angel Batista
- James Remar: Harry Morgan
- Colin Hanks: Travis Marshall
- Edward James Olmos: Professor Gellar
- Christian Camargo: Brian Moser
- Aimee Garcia: Jamie Batista
- Billy Brown: Mike Anderson
- Molly Parker: Lisa Marshall
- Josh Cooke: Louis Greene
- Brandon Eaton: Jonah Mitchell
- Scott Michael Campbell: Norm
- Cherilyn Wilson: Laci (Store Clerk)