|“|| "You're afraid to remember him because you're afraid of what it means."|
"Why do you care so much if I remember him?"
"Because you loved him."
- Tyler Posey as Scott McCall
- Dylan O'Brien as Stiles Stilinski (credit only)
- Holland Roden as Lydia Martin
- Shelley Hennig as Malia Tate
- Dylan Sprayberry as Liam Dunbar
- Linden Ashby as Noah Stilinski
- Melissa Ponzio as Melissa McCall
- JR Bourne as Chris Argent (credit only)
- Ryan Kelley as Jordan Parrish
- Ian Bohen as Peter Hale
- Khylin Rhambo as Mason Hewitt
- Victoria Moroles as Hayden Romero
- Cody Christian as Theo Raeken
- Michael Johnston as Corey Bryant
- Susan Walters as Natalie Martin
- Joey Honsa as Claudia Stilinski
- Pete Ploszek as Garrett Douglas
- Makenna James as Tara Raeken
- The episode title is a reference to Theo's underground prison, where he was tortured by an endless loop of the same hallucination-- he awakened in a cubby in the morgue at Beacon Hills Memorial Hospital, where he would break out and run into his sister, who ripped her heart out of his chest in retribution for him letting her die.
- It is revealed that Mason Hewitt is somehow able to see Corey Bryant when he is invisible, as a refraction of light apparently appears around his silhouette whenever Mason looks at him. It is unknown how he can do this when none of the other pack members and their allies can; Mason suggested it could be due to pheromones or other chemical releases, but it could also be a side effect of his being a (otherwise powerless) Chimera.
- Garrett Douglas reveals his Alpha Werewolf form in this episode, which bears a striking resemblance to Deucalion's Alpha form.
- It is also revealed that Garrett has been faking an American accent since his introduction in Memory Lost; in reality, he has a German accent.
- Garrett is revealed to be able overpower a Ghost Rider, as well as intimidate it.
- It is shown that the Ghost Riders have a unique form of communication among themselves as well as with Hellhounds. Ghost Riders also apparently have the power to control Hellhounds, as they compelled Parrish to attack Theo Raeken, Scott McCall, and Liam Dunbar.
- After eating a Ghost Rider's pineal gland, Garrett Douglas' Werewolf eyes go from red to the same bluish-green of the Ghost Riders' energy. It is unknown in what ways Garrett's supernatural identity and powers have been changed as a result of ingesting the Rider's brain.
- It is implied that the Ghost Riders and Garrett have history, though it has yet to be explored.
- According to IMDB, Theo's sister's name is Tara, though this was not stated in-show.
- Corey Bryant - erased from existence by Garrett Douglas
- Unknown Ghost Rider - traumatic brain injury; killed by Garrett Douglas.
- Beacon Hills Memorial Hospital
- Reception Area
- Peter's Room
- McCall House
- Living Room
- Stilinski House
- Stiles' Bedroom
- Beacon Hills Preserve
- Transformer Shed
- Portal to the Phantom Train Station
- Martin House
- Lydia's Bedroom
- "Under My Skin" by SPC ECO
- Lydia arrives at the Stilinski House and joins Sheriff in the remains of Stiles' bedroom. She looks around the room and sees his bed, clue board, and other objects, but Sheriff can't see anything.
- "Murder Song (5, 4, 3, 2, 1)" by Aurora
- Lydia picks up Stiles' lacrosse jersey and throws it at Sheriff, causing him to be able to finally see it and realize that Stiles really is his son.