Stiles calls Scott, he's lost and thinks he was sleepwalking. He's stuck and thinks something happened to his leg. He asks Scott to please not call his dad and says he has to turn the phone off.
Scott calls for Isaac so they can help Stiles.
Lydia hears Stiles through the radio at school.
When Kira's light bulb goes out, she touches it and it goes on momentarily before it breaks. When her mom comes in to change the bulb, it flashes briefly before she screws it in.
Stiles is in a basement and his foot is in a steel claw trap. The person it the room with him is holding chalk and wrote the backward numeral 5 on the wall. It blew away in dusty smoke.
Sheriff Stilinski asks that they look first for the jeep. He wonders if Scott and his friends can find Stiles by scent. One of his deputies finds Stiles jeep and they discover it's dead because Stiles left the lights on.
Derek helps Scott at the scene and senses that Stiles was struggling -- with himself.
Lydia realizes that the strings in Stiles bedroom give off the sound of people whispering when she pulls them. She hears something about a house. The one that's pinned to the string it's attached to. A mental house center where William Barrow was committed. It's where Stiles is.
What appears to be the Nogitsune is talking to Stiles as if they are one person. Stiles pleads for it to stop saying "we."
Melissa goes to the station to see Agent McCall to lend a hand with the case.
McCall suggests that Stiles has been asleep this entire time. He thinks he's convinced he's in a basement, but he's not really there, but he has an idea about where he might be.
As something is taunting Stiles with "everyone has it but no one can lose it" Melissa and McCall pull Scott from wherever he was hiding.
Isaac gets to Allison's to find out her phone had been turned off. Her voice mail is full, and there are messages in Japanese on it.
As Derek talks through the Nogitsune spirit taking over Stiles, he wonders why it wouldn't take over someone with more power... and puts together the two parts of a battery charger creating sparks.
Lydia starts to question her powers.
Derek wants Kira to tell him everything that happened at the power station with William Barrow.
Sheriff Stilinski shows Derek all of Stiles' symptoms and suggest they do some tests.
Derek and Kira go to the power station and find Stiles' baseball bat. It's magnetized and stuck to the power station. He asks her to tell him everything she knows about foxfire.
Allison and Isaac take her phone to Mr. Yukimura at school to translate what the messages say, and they're in Japanese, warning people to stay away from the fences during an internment camp at Oak Creek during WWII. He said there was no Oak Creek, so they have to be fake.
Stiles gets an MRI to see if he has frontotemporal dementia, which is what his mother had. It's the only form of dementia that can hit teenagers and cannot be cured. It's what Stiles' mother had.
Derek tells Scott that Beacon Hills needs someone like him to protect us. Scott realizes that Scott was struggling with himself to protect Beacon Hills from himself. They find a bag of tools in the power station and a short in the line.
Meanwhile Stiles is in the MRI machine and the doctor has discovered atrophy. The Nogistune is back, screaming that everyone can have it but no one can lose it, what is it as he unwraps his bandaged face to reveal he's Stiles. There is a power surge, Stiles is gone and all hell breaks loose.