In a flash forward, Scott is on the floor of the hospital, gasping, and reaching for his inhaler. The Pathologist crsuesh it beneath his boot and picks Scott up, holding him against the wall. The elevator dings open, and Malia emerges, shifted. She attacks, as the Pathologist tosses Scott away. Melissa rushes to get Scott and hauls him into the elevator while the fight goes on. She gives him a shot of a bronchodialator to help with his asthma symptoms. Melissa shouts for Malia, who breaks out of the Pathologist's grip and runs for the elevator. She barely makes it in time, and the doors close just behind her. Scott looks up at Malia from the floor. "We never should've read that book."
Back in the present, Deputies Clarke and Cordova are at the school at night, because 8 more empty graves have been discovered.
The following morning, Malia and Stiles are with the Sheriff in his office updating the case board. The Sheriff crosses out Tracy's photo. "Chimeras." "Two dead chimeras," Stiles says. "And eight new ones," Malia adds. That's ten in all, but the Sheriff thinks it's probably 11, and he adds Donovan's photo to the wall. The Sheriff confirmed with his tech guys that the camera and the lock on the cell could have malfunctioned because of something electromagnetic--which he now knows the Doctors can manipulate because that's how they got into Eichen House. Stiles can't look at the photo of Donovan. Malia agrees that Donovan must a chimera too. The Sheriff wants to know if he's a failure like Lucas and Tracy. Stiles turns away and stands in the corner, upset and guilty. Malia goes to put a red cross on Donovan, but the Sheriff stops her. "Not until I've seen a body." He then turns and sees Stiles, rubbing his hands together. "You're uncharacteristicaly quiet." Stiles covers for his guilt quickly by bringing up the fact that all the victims are teenagers. "So shouldn't we be trying to figure out why these teenagers?" He suggests that if the Doctors are making such particular effort, like breaking someone out of jail, it must be because they have something in common, which makes their selection non-random.
In Parrish's house, Jordan and Lydia practice hand-to-hand combat. He instructs her to keep her hands up so she can protect her head while keep her eyes on her enemy. They spar, and Jordan tags her. Lydia recovers and tells him she wants to keep going. He's afraid she's going to rip out her stitches, so she pulls up her shirt and shows him the dressing with no visible blood. Lydia tosses her shirt aside, and Parrish takes off his hoodie. They try again, and this time Parrish is able to grab her and pull her in close. He asks her what she did wrong. "Forgot to keep my arms up." He tells her that it's okay because her muscles have memory and with enough practice they will remember for her. Lydia leans back against him, and they both become conscious of being pressed against one another in an embrace. Lydia suddenly has a flash of a Doctor's hand on her arm and then being surrounded by them during her surgery. She makes a pained sound and pulls away from him. She can see her photocopy of The Dread Doctors sticking out of her bag across the room. "What's wrong? What is it?" Parrish asks. "Muscle memory," Lydia tells him.
At school, Scott tells Theo to keep an eye out for people acting a little off. Scott has his copy of the book, too. Theo reminds him that Tracy went on a killing spree after reading it. "You think it' sa bad idea?" "I think Malia almost getting run down by a car could've been bad." He figures that's why they haven't finished reading it yet. Scott tells him that they're going to, but Theo counters that he came looking for a pack, not to watch one fall apart. "That book's all we've got," Scott says. Theo offers to read it, too.
They're all at Scott's house with copies. Lydia complains that her mom's book club usually has more wine. "Well, they also probably didn't read books that cause violent hallucinations," Stiles replies. They've asked Malia to watch over them while they read so there will be someone to stop them from running into traffic like she did. Lydia says she should have her mother read it, so she'll remember her encounter with Tracy. "If it works," Stiles warns. "It has to," she replies. Lydia then explains that she saw the Doctors during the surgery and when she looks at the cover of the book it feels like a memory wants to surface. She wants to know what happened to her. They all start reading. Scott has difficulty concentrating. Kira's vision keeps blurring, like the words are underwater. Scott finally asks if anyone is feeling anything. "Tired," says Kira. "Hungry," Lydia replies. Theo chastises them all with, "I think he meant the book."
In the kitchen, Malia pours Stiles some coffee and notices him rubbing at the wound on his shoulder. She can smell the blood. Theo listens in on their conversation. Stiles claims that the hood of the Jeep fell on him while he was fixing it. To change the subject, he asks her about her recovered memory. "Did it play like a movie in your head or what it like being completely in it again?" "In it." "Was it just the crash? Nothing else?" Malia lies and doesn't tell Stiles about seeing the Desert Wolf. She sees Theo listening, and he now knows that he carries one of her secrets. Kira "rests her eyes" and ends up falling asleep.
Meanwhile, Liam is an Sinema to give Hayden more of the money he owes her. A club goer complains to Hayden that his glow stick broke, but she explains that they just run out of juice. The guy asks for his money back, so she just gives him another glow stick. "God, I had all-ages night." Liam offers her $43, even though she said she doesn't want his money. He insists that he owes her $200, and he already feels bad enough about their past that he wants to make up for it. Just then the power shuts down in the club. Everyone cheers and shakes their glow sticks. Liam follows Hayden into the back. She tells him that if he's trying to be a good guy, she doesn't care. He admits that he's trying to make up for sixth grade. Hayden throws one switch to get the power back on but has trouble with the second. Liam covers her hand with his and helps. "You want to keep hating me, go for it. You said I owe you $200. So here's $43 more." Hayden finally takes the money, and Liam leaves.
Back at Scott's house, everyone has fallen asleep but Theo. Theo goes up to Scott's room and records Kira speaking in Japanese. "Watashi wa shi no shisha da."
The next morning at school, they think maybe they have to trigger the memories somehow. But since they don't know which memories, they can't tell what the triggers would be. Stiles, Scott, and Kira warn each other to be on the lookout. The lights in the school flicker, but Kira claims it isn't her.
In AP Biology, Lydia and Theo see Sydney pull out a clump of hair. Lydia wonders if she's a chimera. The AP Bio teacher is telling them about how the African Cane Toad was introduced to Australia to get rid of the grey-backed beetle. This worked, but the toad then kept eating other things too. And everything that tried to eat the toad, from crocodiles to household pets, died from the poison they secreted. It's an example of an invasive species. "Once an invasive species is introduced, everything changes." Sydney leaves class, putting her drop form on the desk as she goes. Lydia goes to follow her, but Mrs. Finch tells her that it's for the best. Lydia goes anyway. Scott looks at his own drop form. Lydia finds Sydney in the counselor's office, looking for her mom. She asks her if she's okay. Sydney shows her more hair that's falling out, and Lydia asks how long it's been happening. "Three years." "Years?" Sydney explains that it's stress. She's tried everything but she can't get it under control. "Have you tried not taking the hardest classes in school?" Lydia asks, making her laugh. Lydia asks if she can see it. Sydney shows her a bald spot just above her ear, but when she does, it suddenly becomes a bloody hole.
Lydia stumbles back and has a vision. She hears her mother telling her: I told you to stay in the car. Lydia, I told you to stay in the car. Lydia wakes up into a vision. She's in a concrete facility, and she's wearing bright red shoes. She hears a drill and sees her mother kneeling next to a tub, where Lorraine is lying. She's drilled into the side of her head. "They're coming, Lydia. They're coming for all of us," Lorraine says. Scott and Theo are there when Lydia comes out of the vision. She tells them that she didn't remember anything about the Dread Doctors or her surgery. It was a memory about her grandmother at Eichen House. Natalie comes rushing in then to check if she's okay. Lydia tells her that she just fainted.
Meanwhile, Kira is in the library trying to read the book. Mason appears next to her. "Not into sci-fi?" He thought they were supposed to finish reading it last night. Kira admits to him that she can barely read it and she doesn't know why. Mason sits next to her and asks if she speaks Japanese. "No. I'm also half-Korean and I don't speak Korean. And I'm pushing a C-average in English." Mason explains that he's been researching kitsunes. "Do you know why people in Japan answer the phone 'moshi moshi'?" Moshi means hello, but there's a reason why they say it twice. Fox spirits have difficulty with language. So the way they prove they're not a fox on the phone is to say moshi twice. It's a language trick that confuses kitsunes. The book is one long language trick, so it's confusing Kira's kitsune spirit. The light next to them flickers, and Kira swears again that it wasn't her.
After AP Bio, Scott goes to give his drop form to Mrs. Finch. He forgot to sign it, and she asks him why he's dropping. He claims a scheduling thing, and she asks him why he took it to begin with. She believes it's a pre-req for the college he wants. Scott tells her that it's too much time and too much work. "To become a veterinarian?" Scott suddenly starts having a memory, while Mrs. Finch tells him she doesn't think he should drop. Scott starts having an asthma attack. He has a memory of a dog leash covered in blood. Then dropping a leash. There's a dog attack. Scott sees himself as a child being wheeled into the hospital. "Mom, where's Roxy?" he asks. He's having trouble breathing. As the memory goes on, Scott's breathing gets worse. Mrs. Finch asks him where his inhaler is. When he can't answer, she orders the other students to find someone with an inhaler.
Outside, Liam and Hayden are practicing their respective sports. They get into a competition. Mostly it's Liam trying to impress her. Mason and Brett are sitting on the bleachers talking about the supernatural warning signs they can look for. Brett offers that able to see in the dark is a good clue. Liam throws a little too hard and hurts the goalie.
Brett asks Mason what the deal is between Hayden and Liam. Mason explains that in sixth grade Liam was getting into a figth with another kid. Hayden accidentally walked into the fight and got punched. She has a broken nose in her yearbook photo. But she hit Liam back, and he had a broken nose in his photo too.
A student comes running out onto the field shouting for anyone who has an inhaler. Liam immediately knows it must be Scott. He rushes into the school and puts the inhaler in Scott's hand, but Scott is too out of it to use it himself. Liam lets his eyes glow and growls at Scott, which pulls him out of it enough to use the inhaler. Hayden saw Liam help and smiles to herself a bit.
Lydia and Stiles go to the hospital because Lydia is determined to find the repressed memory she's looking for. The one she had wasn't the right one. Lydia's now thinking that hte vision she had during her surgery wasn't because of the Doctors but because of her banshee powers. "It's not my memory, Stiles. It's someone else's."
Theo is in the gym at school working out. He hears Malia coming and smiles to himself as he takes his shirt off. She tries not to notice. Malia asks him why he hasn't said anything about her Desert Wolf memory. "I didn't think you wanted me to." She doesn't. She asks if he wants to know why, but he doesn't. He sits down on the butterfly machine and starts doing lifts. Malia grabs the bars to stop him. "You think you're doing me a favor? Like I'm going to owe you now?" "I don't need any favors." "Then what do you want?" "I want in the pack." Malia points out that that isn't up to her. Theo tells her that he's okay with whatever she's planning. Malia lets go of the bars and leaves.
Deputy Clarke is Hayden's sister! She catches up with her and hands her a bottle of medication that almost got ruined in the wash. One bottle of Hayden's meds is $200. Liam overhears this. "Is that Liam Dunbar?" Clarke asks. "He got cute." Liam smiles to himself.
Scott is sitting in the boys locker room, looking at his inhaler. Theo asks him if he'll be okay. Scott says yes. It was a psychosomatic thing because of the memory that came back to him. Scott asks Theo if he wanted to talk about something. Theo demures, but then tells Scott he recorded Kira's Japanese mutterings. Theo translated it to "I am the messenger of death." By Scott's look, Theo asks if it gets worse than just her saying this. Scott admits that Kira's aura looks like it's taking over. "Something's happening. And to be honest, I doni't know if I can trust her anymore." The lights flicker again, and they both hear sounds in the basement.
Stiles and Lydia head into the operating room. Stiles tries to turn the lights, but they aren't working. Lydia tells him to ask someone. Stiles thought her powers were more of an auditory thing. "I still want to see what I'm hearing." Melissa tells Stiles that the floor has been having maintenance issues for the last hour so thre's only back-up lighting. Stiles gets in the elevator and sees a woman's reflection behind him. He starts following her and realizes that it's his mother. Malia meets up with Scott and Theo and reports on everyone's whereabouts. On top of the hospital, one of the chimera is eating a power cable.
At Sinema, the bartender tells a boy that the base pay is crap but he can make up to a thousand in tips if he's hot. He has the guy pull up his shirt, but he isn't quite up to snuff. Liam offers Hayden another $45, but she doesn't want it. Phil, the bartender, takes half her money anyway. Liam insists that she take the money for her medication, but she insists that it wasn't his fault the drinks spilled. She tells him her pills are mycophenalate, for a kidney transplant she had a few years ago. She works at Sinema so her sister doesn't have to pay for all her bills. Liam asks her if Phil really takes half her tips. "And never stops bragging about it. Just listen to him." Liam does, but it requires using his werewolf senses to do so. Liam realizes that Hayden shouldn't be able to hear the conversation Phil is having. He asks her if she'll close her eyes. She thinks it's some kind of trick. Liam begs, and eventually she agrees. He grabs a glow stick and breaks it and holds it up next to her face. When she opens her eyes, they reflect the light.
Meanwhile, Lydia is able to hear the Doctors talking in the operating room. She can hear them repeating the same word: Hayden. She sees a boy tied down to the table begging them not to hurt him. The Surgeon peels back the skin on the boy's side, revealing blue flesh. "Your condition worsens."
Stiles is up on the roof, following the image of his mom. He asks her what she's doing, and then his dad is there. "Claudia? What are you doing up there?" "I couldn't stand to be in that room anymore. Now with him looking at me like that. He's trying to hurt me." She's talking about Stiles. "He's trying to kill me." Stiles gets tears in his eyes listening to her. The Sheriff gets her to step off the edge of the roof. He tells her to remind herself that it's the disease, that the dementia gives her delusions. She insists that Stiles is trying to kill her. When Stiles looks down, he sees the shadow of himself as a boy when he saw this scene firsthand. Claudia tells him to stop looking at her like that, and she attacks him. She starts slapping him, and Stiles falls down. The attacker becomes the chimera who was eating the power cords.
Scott, Malia, and Theo arrive at the hospital. Scott tells them to go find Stiles and Lydia. Scott runs into The Pathologist while looking for his mom. He slams Scott against the wall and zaps him in the chest. Scott tries to get his inhaler.
On the roof, the chimera attacks Stiles, but Stiles fends him off. Theo arrives and takes on the chimera for real.
The Pathologist stomps on Scott's inhaler--a return to the scene from the beginning. The elevator opens with Melissa and Malia, and Malia attacks. Melissa rescues Scott and injects him to stop the asthma attack. Malia runs from the Doctor, and they escape.
Theo continues to fight the chimera. He gets the guy by the throat, and then kills him. Stiles watches. "Stiles. You can't say anything. Please, don't say anything." "Why not?" "Because I never said anything about Donovan." And then Stiles realizes he's being blackmailed.