|“|| Deaton: "I was hoping we could talk. My name is Dr. Alan Deaton."|
Valack: "Oh, I know your specialty, Dr. Deaton, and I know it's not cats and dogs."
Deaton: "I'm here because of what you know about South American mythology."
Valack: "No. You want to know about Kate Argent-- you want to know about La Loba, the Bone Woman."
Deaton: "I need to know what she did to Derek Hale... and if he's dying."
Deaton: "Because of a promise I made... to a woman I loved."
Dr. Deaton captures Patrick, a Wendigo who escaped from Eichen House and who was on the Deadpool for $250,000, and returns him to a secret area of the hospital housing various supernatural creatures as a favor to Conrad Fenris. In exchange, Deaton requests to meet with one of the supernatural ward's inmates, a human former-doctor with a third eye named Dr. Gabriel Valack, who claims to have knowledge regarding what Kate did to Derek. Deaton obtains the information by looking into Valack's third eye, allowing him to see what Kate was planning in an illusion, though he is sent into a coma as a result.
Meanwhile, Liam is suffering from nightmares and hallucinations of the Berserkers following his battle with them at the hospital. Lydia appears at Derek's loft in the middle of the night, and when Derek and Braeden found her, she screams. Chris tracks down where Kate has been hiding in the sewers, but encounters Peter and one of the Berserkers instead. Peter impales Chris with a metal bar, pinning him to a wall so he can't warn the McCall Pack to his plans with Kate before he leaves. As Stiles and Liam prepare for the first lacrosse game of the season, Scott and Kira go on their first official date in Derek's loft, but are ambushed by Kate and the other Berserker. Scott and Kira put up a good fight, but are eventually defeated, and after Kate taunts Scott regarding what she perceived as his role in the decimation of the Argent Family, she reveals that she is taking them both to La Iglesia.
Lydia is able to awaken Deaton from his coma, presumably using her scream. Once he's conscious, he informs the group that Scott and Kira have been abducted, and that Kate has taken them to Mexico. Peter shows up at the lacrosse game to see Malia, informs her that he has found her mother, and offers her a deal-- he will give Malia her mother's identity if she helps him to kill Kate. During the game, Brett helps Liam to learn control over his fear, as part of Brett's debt to Scott for saving him and his pack. Deputy Parrish finds Chris in the sewers. Working together, they are able to free Chris, but in the process, Parrish's eyes glow orange. Kate imprisons Scott and Kira in the abandoned church in La Iglesia (the abandoned town in Mexico where she was keeping Derek at the beginning of the season), and informs Scott that she is planning to turn him into a Berserker to use him in her final revenge against him; his pack will believe that Scott is one of her original Berserkers and will kill him without realizing who he really is.
- Tyler Posey as Scott McCall
- Dylan O'Brien as Stiles Stilinski
- Tyler Hoechlin as Derek Hale
- Holland Roden as Lydia Martin
- Shelley Hennig as Malia Tate
- Arden Cho as Kira Yukimura
- JR Bourne as Chris Argent
- Melissa Ponzio as Melissa McCall
- Linden Ashby as Sheriff Stilinski
- Ian Bohen as Peter Hale
- Orny Adams as Coach Bobby Finstock
- Seth Gilliam as Dr. Alan Deaton
- Jill Wagner as Kate Argent
- Meagan Tandy as Braeden
- Dylan Sprayberry as Liam Dunbar
- Khylin Rhambo as Mason Hewitt
- John Posey as Dr. Conrad Fenris
- Steven Brand as Dr. Gabriel Valack
- Ryan Kelley as Deputy Jordan Parrish
- Cody Saintgnue as Brett Talbot
- Claire Bryétt Andrew as Sydney
- Mark Elias as Patrick Clark
- Dakota Gorman as Kalissa
- Jake Mateo as Referee
- The title refers to Deaton and his confession that he once loved Talia Hale and made a promise to protect her son Derek.
- It is revealed that Kate can create Berserkers as well as control them, though it is still unknown if this is true of all Werejaguars or if it is a power unique to Kate herself.
- Liam and Brett seem to reconcile, as Brett is grateful that Scott and his pack saved Satomi's pack from the Deadpool assassins.
- Peter tells Malia that he will help her find her mother, the Desert Wolf, but only if she kills Kate. Since Peter and Kate were actually working together, it is unclear if this was simply meant to keep Malia from figuring this fact out, or if he really did want Malia to kill Kate in order to tie up his loose ends.
- Kate mentions the Greek goddess Artemis, who is most commonly believed to be the daughter of Zeus and Leto and is the twin sister of Apollo. She is the goddess of the hunt, wild animals, wilderness, childbirth, and virginity, and is also known of being a protector of young girls and women, making her an interesting choice of a metaphor for Kate, a Werejaguar and a Hunter.
- The story Kate tells of Artemis and Actaeon is a commonly-told one and is very similar to other accounts of the story. Actaeon was a well-known hunter in Greek mythology, the son of Aristaeus and Autonoe, and, like Hercules, was trained by Chiron, a centaur.
- Patrick's Meat Locker
- Eichen House
- Closed Unit
- Valack's Room
- Closed Unit
- McCall Pack
- Dining Room
- Liam's House
- Liam's Bedroom
- Derek's Loft
- Stilinski House
- Stiles' Bedroom
- La Iglesia
- Temple of Tezcatlipoca
- The Obsidian Room
- Temple of Tezcatlipoca
- Beacon Hills High School
- Coach Finstock's Classroom
- Weight Room
- Lacrosse Field
- Locker Room
- Beacon Hills Tunnels
- "Hide" by Little May
- Malia tries to awaken Stiles for school, and the two start to make out in his bed
- "I Need My Memory Back" by The Glitch Mob
- Liam is lifting weights in the weight room when he gets a Berserker flashback and loses his strength momentarily. Scott rushes into the room to save him from being pinned by the benchpress
- "Given the Chance" by The Kite String Tangle
- Scott and Kira have a date in Derek's loft, and the two are making out on the couch when Kate and one of her Berserkers burst through the windows
- "Gold" by FMLYBND
- The lights on the lacrosse field are turned on in preparation for the Beacon Hills High vs Devenford Prep game
- "Faded" by Afrojack
- Stiles assures Liam that the team will be fine without Scott, but then begins to worriedly text Scott to make sure he's okay
- "Belgium" by Gesaffelstein
- Brett sees that Liam is scared and in the middle of a panic attack caused by his Berserker hallucinations and tries to calm him down
- "Cain" by Cousin Marnie
- Kate performs the ritual to turn Scott into a Berserker