|“|| "There was a suicide, huh?"|
"Is it a Monday? There's a much higher rate of suicide on Mondays. [...] I heard it, by the way. It happened in the stairwell, right?"
"Yeah. How'd you know that?"
"I heard the echo."
"What do you mean?"
"It's this place-- something about the way that it was built. Everything echoes. That's why they call it "Echo House."
(* There is no official synopsis released by MTV, so this summary is written by TWP Wiki contributors)
Stiles checks himself into Eichen House, a mental health facility. Chris Argent and Deaton are working together to find a special scroll that could reveal a way to exorcise the Nogitsune from Stiles' body. While in Eichen House, Stiles encounters Malia Tate, the Werecoyote he and Scott saved who isn't pleased to see him again. After group therapy, Stiles is told by Ms. Morrell that he must stay awake before she gives him amphetamines to help him in this task, explaining that vessels are weaker when they are asleep; however, she warns him that if his pack can't find a way to save him, she will use pancuronium bromide to kill him and save Beacon Hills from the Nogitsune's reign of terror.
Stiles enlists Malia in a plan to access the basement. After being put in the "quiet room," Stiles is saved by Malia, and the two head to the basement together, where they share a passionate encounter. Soon after, Malia realizes that the wall with the kanji carved into it is hollow, and the Nogitsune's deceased former vessel lies behind it. The Nogitsune gives Stiles an ultimatum; allow it in or watch Malia die via trephination, with Stiles ultimately deciding to let the Nogitsune take control once again now that the letharia vulpina has left his system. After Scott, Allison, Kira, Lydia, and the twins obtain the scroll from Katashi's belongings, Deaton reads the scroll and informs them that the Nogitsune's host body needs to change its form in order to exorcise the Fox spirit, suggesting that giving Stiles the Bite and turning him into a Werewolf may be the only one to save him.
- Tyler Posey as Scott McCall
- Crystal Reed as Allison Argent
- Dylan O'Brien as Stiles Stilinski/Nogitsune
- Tyler Hoechlin as Derek Hale
- Holland Roden as Lydia Martin
- JR Bourne as Chris Argent
- Linden Ashby as Sheriff Stilinski
- Daniel Sharman as Isaac Lahey
- Seth Gilliam as Dr. Alan Deaton
- Bianca Lawson as Marin Morrell
- Arden Cho as Kira Yukimura
- Charlie Carver as Ethan
- Max Carver as Aiden
- Shelley Hennig as Malia Tate
- Vernee Watson as Eichen House Attendant
- Matt Shively as Oliver
- Aaron Hendry as Nogitsune/Brunski
- Ivonne Coll as Araya Calavera
- Geno Segers as Kincaid
- Ryan Kelley as Deputy Jordan Parrish
- Maya Eshet as Meredith Walker
- Gina Holden as Claudia Stilinski (deleted scenes only)
- Nichole Bloom as Rinko
- Robin Johnson as Mary (as Robin Kiah Johnson)
- Pamela Wistrom as Asylum Patient
- The title refers to Eichen House, which, according to Oliver, is referred to as "Echo House" due to the fact that the way the building was built meant that every sound echoes through it.
- There is another riddle said by an Eichen House patient who hung himself in front of Stiles this episode-- "I'm part of the bird that's not in the sky. I can swim in the ocean and still remain dry. What am I?" The answer is "its shadow," much like the riddle told to Stiles in Riddled.
- Eichen House Patient - suicide/hanging; killed by himself (possibly influenced by Nogitsune)
- Eichen House
- Administrative Office
- Stiles & Oliver's Room
- Common Area
- Men's Shower Room
- "Quiet Room"
- Beacon County Sheriff's Department
- Holding Cells
- Interrogation Room
- Beacon Hills Animal Clinic
- Reception Area
- Exam Room
- Argent Apartment
- Chris' Office
- "No One's Here To Sleep" by Naughty Boy ft. Bastille
- Stiles walks into the men's restroom to take his pills and finds Malia showering there.
- "Hustler" by Conway
- Kira shows off her newly-learned sword-fighting skills.
- "Feel Real" by Deptford Goth
- Stiles and Malia make out on the downstairs couch in Eichen House.
- "Shout" by Ida Redig
- Malia leaves Eichen House to find Scott after Ms. Morrell tells her where to go.