Stilinski drives Stiles to the Eichen House mental institution. Scott meets them outside and warns that he can't help Stiles when he's in there. Stilinski's going to see if a specialist can help him. Stiles asks Scott to make sure he can never get out. They go inside where a nurse describes the process Stiles will go through. Stilinski worries about the pillow he forgot and starts to freak out. He doesn't want to check him in but Stiles insists he'll be fine. The nurse leads Stiles up the stair case to his room. On the way, Stiles notices a man at the top of the stairs preparing to hang himself. He tries to run up but it's too late for the man. He looks down and sees the bandaged face and teeth of his demon on another floor.
Deaton talks to Argent on the phone and warns that the plant he used on Stiles will wear off in a few days. The other problem is that the scroll that tells how to exorcise the demon was never found. All Deaton knows is that Kincaid, one of Katashi's men, was the last known person to have the scroll. Allison tells Deaton that she may know where it would be.
Stiles tries to convince the nurse to let him use the phone but she won't. He enters his room where he meets his room mate Oliver. Stiles gets no sleep during the night. In the morning, Oliver leads him around the grounds. They overhear a girl talking on the phone about Stiles. He picks up the phone but Oliver says that the lines are disabled for 24 hours after a suicide. Stiles runs into Malia but she punches Stiles. Attendants grab both of them and Stiles is pushed to the ground. He realizes the floor he's pushed against has holes to allow light in and it was the room underneath that he was trapped in with his demon. Ms. Morell asks what he saw and he says he's been down there before.
Derek and Argent are still locked up and Derek hears that the police are moving the evidence. People are dead because of Stiles but Argent reminds him it may not be Stiles in charge of himself. This reminds him of a berserker who became a bear that he had to take down. He felt no remorse when he did this. Derek asks how he would feel with Stiles. Argent would feel remorse for Stiles but not the demon.
At Eichen House, Ms. Morell holds a group meeting. She asks Malia about the guilt she feels. It often becomes physical and isn't just psychological. Stiles sees signs of his demon and feels nervous. Morell calls for a break when she notices red marks on Stiles' neck. She examines the marks and says they usually appear on those struck by lightning. Morell warns that when the marks fade, the demon's grip over him will return. She hands him pills so that he won't fall asleep and become vulnerable. If Stiles' friends don't help him by the time the marks fade, she will be force to kill him.
Stiles tries to get in the basement but Oliver says only Brunsky, the head orderly, has the keys. Oliver suggests tricking Brunsky to get the keys.
Allison tells the Twins and Scott about the Katashi evidence being moved. Lydia says they will be robbing an armored car before it gets to federal lockup.
In the bathroom, Stiles talks to himself when he notices Malia is showering. He asks why she punched him and she isn't thankful for being rescued. She wants to go back to being a coyote and Stiles offers a trade. If she helps him get the basement keys he will put her in touch with someone who can help her transform into a coyote at will.
Lydia and Allison outline the plan to steal the evidence. Allison says they need to do this because they are losing Stiles and Argent is in jail for murder.
Malia gets in a fight with Oliver as part of their plan. She takes Brunsky's keys and hands them off to Stiles.
Argent was told his lawyer is there for him but he's greeted by someone else. The woman calls him Christof.
Stiles tries to use the keys to enter the basement. Brunsky shows up and says no one has the key to that room. He takes Stiles to the quiet room and asks where he got the pills from. An orderly injects Stiles with a sedative and he falls asleep while insisting he needs to stay awake.
Kira shows up at Scott's and offers to help with the theft. She pulls out a katana and shows Scott her recently acquired skills. He allows her to come.
Stiles dreams that he's trapped in a locker. His demon is outside the locker and wants to be let in. He wakes up to Malia above him. She broke the lock to get into his cell. She tells him of another way into the basement. It's through the closed unit where the real psychos are held.
At the police station, Kira runs and places a tracker on the armored truck. Deputy Parrish enters the passenger door but sees the driver is dead. He moves around the back of the vehicle but Kincaid exits the vehicle and knocks Parrish out.
The woman talks to Argent about the code. She says his family is very complicated and he asks what she's fishing for. She doesn't fish, she hunts.
Allison and Scott confront Kincaid about the finger. They want it but he says the scroll inside is worth $3,000,000. Kira jumps on him but it does nothing. He howls and begins to shift.
Malia leads Stiles into the basement room. He doesn't know what he's looking for but it has something to do with the backwards 5 carved into the wall. He doesn't want to tell her more but she promises not to judge.
Scott attacks Kincaid but he's too strong. Kincaid says he has alpha eyes but not the strength. The Twins join the fight and overpower Kincaid.
In the basement, Malia finds evidence of old techniques Eichen House used. They think that's why no one is allowed down there. The lines on Stiles' back are almost gone and he tells her that's bad. She's always been cold since returning to human form and Stiles warms her up. The two hold hands and then kiss. She says she wants to try something else and takes her shirt off.
Scott and Lydia stop the Twins from going too far and killing Kincaid. Scott reminds them they're there to save a life, not end one. He takes the scroll from the silver finger.
Malia notices something and finds the wall with the backwards 5 on it is hollow. Stiles breaks through it and they find what he says is the demon. She reaches into one of his pockets and hands a piece of paper to Stiles. He wants to get it to Scott but Oliver uses a taser gun on him. He stole it from Brunsky and also tases Malia. He uses a sedative on Malia before turning on. Oliver picks up a tool and threatens to drill a hole in Stiles' head to let the evil out. Stiles passes out and wakes up restrained in a chair. Oliver moves in with the tool but the demon speaks. Stiles realizes the demon is the one who's controlling Oliver. The demon wants into Stiles and warns that Oliver will drill into Malia's head if he doesn't. Stiles lets the demon in and stops Oliver from hurting Malia.
Deaton reads the scroll that Scott retrieved. It says that one method of expelling the demon is to change the body of the host. Scott thinks this means he needs to turn Stiles into a werewolf.
As Malia leaves the Eichen House, she tells Morell that she's looking for Scott McCall. Morell says she knows where Scott can be found. Malia smiles as she leaves and her eyes glow blue.