|“||Someone is trying to make supernatural creatures with non-supernatural means. And, whoever they are, they're somehow managing to blur the lines between science and the supernatural.||”|
In a flashback, Jordan Parrish tells Lydia Martin about a dream where he carries a body to the Nemeton before his body bursts into flames to begin to char the body he placed there, along with all of the others around it, though he leaves that part out of his story. In the present, the Dread Doctors abduct Donovan Donati from his holding cell at the Beacon County Sheriff's Station, taking advantage of the chaos caused by Lydia Martin's injuries at the hands of Tracy Stewart and Tracy's subsequent murder by the Doctors to do so without detection. Noah Stilinski and Alan Deaton have an argument regarding what they will do about Tracy's body; Noah argues that her body is evidence and that they need to do an autopsy per the law to find her murderer, while Deaton insists that, unless Noah is willing to reveal the existence of the supernatural world to the human world, he himself is better equipped to examine the body and its severed tail, especially since Tracy's scales, fangs, and claws had not retracted after her death.
Lydia is taken to the hospital for surgery, where she begs her mother Natalie Martin to not tell anyone what she saw during her battle against Tracy, but Natalie, in denial about the supernatural, insists that she saw nothing but a psychotic girl. Melissa informs Theo Raeken that his tourniquet saved Lydia's life, and Malia reminds everyone about the masked men who killed Tracy.
The Dread Doctors transform Donovan into a Wendigo-Lamprey hybrid, and Theo is revealed to be working with the Doctors. Deaton informs Scott and Kira that Belasko was a Werewolf-Garuda hybrid, while Tracy was a Werewolf-Kanima hybrid. They were both created artificially, explaining why Tracy was immune to mountain ash, which leads Deaton, Scott, and Kira to realize that someone is creating hybrid supernatural creatures, which Scott dubs Chimeras.
Liam agrees to be Mason's wingman at a nightclub. While there, Liam argues with a girl named Hayden, while another Chimera, Lucas, tries to seduce Mason. Scott, Kira, Liam, and Brett manage to subdue Lucas, who is revealed to be a Werewolf-Scorpion hybrid. Kira loses control of her Kitsune nature and attempts to kill Lucas, shouting "I am the Messenger of Death!" in Japanese, but Scott stops her and snaps her out of it. The Doctors appear and kill Lucas themselves, stating that he was a failure. Malia discovers a book in Tracy's bedroom called The Dread Doctors which features pictures of the Doctors on its cover. Parrish takes Lucas' body to the Nemeton in a trance and sets them both ablaze. Elsewhere, Stiles is attacked by Donovan, who has been fully transformed into a Chimera.
- Tyler Posey as Scott McCall
- Dylan O'Brien as Stiles Stilinski
- Holland Roden as Lydia Martin
- Shelley Hennig as Malia Tate
- Arden Cho as Kira Yukimura
- Dylan Sprayberry as Liam Dunbar
- Melissa Ponzio as Melissa McCall
- Linden Ashby as Sheriff Stilinski
- Seth Gilliam as Dr. Alan Deaton
- Ryan Kelley as Deputy Jordan Parrish
- Cody Christian as Theo Raeken
- Khylin Rhambo as Mason Hewitt
- Susan Walters as Natalie Martin
- Ashton Moio as Donovan Donati
- Victoria Moroles as Hayden Romero
- Michelle Clunie as Mrs. Finch
- Todd Williams as Dr. Geyer
- Benita Robledo as Deputy Valerie Clarke
- Michael Johnston as Corey
- Cody Saintgnue as Brett Talbot
- Eddie Ramos as Lucas
- Marti Matulis as The Surgeon
- Douglas Tait as The Pathologist
- Caitlin Dechelle as The Geneticist
- Claire Bryétt Andrew as Sydney
- Billy Snow as Phil
- Kelsey Chow as Tracy Stewart (uncredited)
- The title refers to Lucas, specifically when the Dread Doctors told him that his condition was terminal, and that he was a "failure."
- Deaton figures out that the hybrid creatures Beacon Hills has been dealing are technically not supernatural but still have supernatural abilities.
- It is confirmed that Theo is working with the Dread Doctors in this episode, though why he is working with them has yet to be revealed.
- Stiles is attacked by Donovan at the end of the episode, when he reveals he is part-Wendigo and part-Lamprey.
- Lydia suggests that the Nemeton might even make supernatural creatures stronger in addition to being a beacon that draws the supernatural to Beacon Hills.
- Lydia sees the Dread Doctors during her surgery when the anesthesia starts to kick in, suggesting she may have been manipulated by them as well.
- Brett is revealed to be bisexual or pansexual in this episode, which was later confirmed in interview with Cody Saintgnue.
- This episode features music by the DJ DallasK, who plays his music at Sinema. This is similar to Season 3's Illuminated, which featured music by The Bloody Beetroots at the party at Derek's loft, and Season 4's The Dark Moon, which featured music by Deorro that played at the club in the Calavera Compound.
- Parrish's Apartment
- Living Room
- Beacon County Sheriff's Station
- Holding Cells
- Sheriff's Office
- Dread Doctors' Operating Theater
- Beacon Hills Memorial Hospital
- Emergency Room
- Reception Area
- Operating Room
- Lydia's Room
- Corey's Room
- Beacon Hills High School
- Mrs. Finch's Classroom
- Parking Lot
- Stewart House
- Tracy's Bedroom
- Beacon Hills Preserve