|“|| "You know, Einstein was right. Imagination is more important that knowledge. It was like something out of Greek mythology, ike the Furies coming down to punish Orestes. You don't know what I'm talking about, do you?"|
"Was- was he the one who stabbed out his eyes?"
"God, that's Oedipus, you dumbass! The Furies are the deities of vengeance. Their tears ran of blood, and they had snakes for hair. If there was a crime who went unpunished, the Furies would do the punishing. Jackson is my Fury."
Matt takes Scott, Stiles, Melissa and Sheriff Stilinski hostage. Gerard persuades Allison to exact revenge on Derek for bringing her mother to suicide. Matt reveals to Scott his reason for the murders: in 2006, all the victims were at a party at Isaac's house, where Matt had come to meet Isaac. They had thrown Matt in the pool and left him to drown despite him yelling that he can't swim. Melissa finally sees Scott as a werewolf. Gerard drowns Matt in the lake and becomes the Kanima's new master.
- Tyler Posey as Scott McCall
- Crystal Reed as Allison Argent
- Dylan O'Brien as Stiles Stilinski
- Tyler Hoechlin as Derek Hale
- Holland Roden as Lydia Martin (credit only)
- Colton Haynes as Jackson Whittemore
- JR Bourne as Chris Argent
- Linden Ashby as Sheriff Stilinski
- Ian Bohen as Peter Hale
- Seth Gilliam as Dr. Alan Deaton
- Michael Hogan as Gerard Argent
- Melissa Ponzio as Melissa McCall
- Stephen Lunsford as Matt Daehler
- John Wesley Shipp as Isaac Lahey
- Noree Victoria as Night Officer
- Fred Cruz as Sean Body
- David Elson as Kanima
- Eaddy Mays as Victoria Argent
- Morgan Ayres as Sean Long (archive footage) (uncredited)
- Andrea Laing as Kara Simmons (archive footage) (uncredited)
- Meghan Moonan as Jessica Bartlett (archive footage) (uncredited)
- Brandon Stoughton as Tucker Cornish (archive footage) (uncredited)
- The title refers to the Furies of Greek mythology, which Matt Daehler referenced in a conversation with Scott McCall to describe why he used Jackson Whittemore as his weapon of vengeance against the people who almost let him drown as a child.
- Night Officer - mauled to death; killed by Jackson Whittemore/Matt Daehler (indirectly)
- 3 Sheriff's deputies - mauled to death; killed by Jackson Whittemore/Matt Daehler (indirectly)
- Matt Daehler - drowned; killed by Gerard Argent
- Whittemore House
- Jackson's Bedroom
- Stilinski House
- Stiles' Bedroom
- Beacon County Sheriff's Department
- Sheriff's Office
- Holding Cells
- Beacon Hills Memorial Hospital
- Jessica Bartlett's Room
- "The White Room"
- Hale House
- Argent House
- Allison's Bedroom
- Lahey House (flashbacks)
- "Night" by Zola Jesus
- Allison angrily strips her room of anything with sentimental value, leaving only her weapons and other hunting materials.