Mrs Martin is counselling a student named Tracy at the high school. The girl is distracted by visions of a crow pecking against a window and a skylight banging in the rain.

Mrs Martin asks if the girl is getting enough sleep and she admits that she's not. The teacher explains that circadian rhythms are different for young people in that the teenage body produces a natural sleep chemical called melatonin late into the morning. Meaning a student's brain is still sleeping long after classes begin.

Tracy explains that she gets night terrors which Martin describes as Parasomnia.

(Parasomnia is actually a catch-all phrase for any sleep disturbance not related to Sleep Apnea. Despite the dramatic name, "Night Terrors" can be mild to severe feelings of great fear upon waking up)Rough Night For Tracy

Tracy says she usually doesn't remember what causes her fear but relays a story of one particularly stormy night when she woke to find a crow pecking against the skylight over her bed. Tracy has a silver leaf-shaped necklace hanging on her nightstand.

The crow is gone and as Tracy settles into sleep again, she sees a masked figure outside her window. She bolts awake and scrambles to turn on the bedside lamp. When she turns back the figure is gone. She makes her way to the window and checks to make sure it is locked.

She turns off the lamp and tries to go back to sleep but is quickly woken by a breeze blowing in from the now open skylight. The lamp next to her bed no longer works. In the darkness, she climbs up on a chair and attempts to reach the latch for the skylight. Straining, she manages to get it closed and locks the skylight. At that moment, a black-gloved figure grabs the chair leg and yanks it out from under her and she falls.

Back at school, Tracy explains that her father found her on the floor and that the skylight was sealed shut a couple of years back for weatherproofing.

Martin takes this to mean that much of what she experienced was just a dream. She explains a theory that one of the biological functions of dreaming is to present the brain with threatening events as a way to rehearse for real-world situations. She diagnoses Tracy with normal anxiety of a form common to seniors in high school.

As Tracy stands to leave, she begins to cough. Eventually, she throws up a torrent of viscous black liquid and black feathers. She asks Mrs Martin if this is part of common anxiety.

The Rules Have Changed

Scott is at work performing an intramuscular injection in the hind leg of a wirehaired mix. Deaton is overseeing his progress. Scott finishes the injection but removes the needle in a way that hurts the dog. It snaps at him. Deaton chuckles saying the dog is a little one but his teeth are still sharp. Scott apologizes to the dog and returns it to its owner, a little girl.

The little girl, Stephanie, calls Scott "Dr McCall." He corrects her that he is not a doctor "yet."

Deaton is examining the claw from the unnamed creature that attacked Scott at the school. He says it is less like a claw and more like the talon of a harpy eagle. While Scott wonders aloud how a werewolf gets talons, Deaton says the more interesting mystery is how the talons somehow absorbed Scott's power.

Deaton says the only creature capable of absorbing Scott's true alpha power would be a beta of his own making, someone like Liam.

Scott wonders if the same would be true of a beta that he did not make but that he allowed into his pack. He's talking about Theo. Deaton says normally the answer would be no, but, apparently, the rules of the supernatural are not as rigid as they believed or someone is trying to change the rules.

Stiles Investigates Theo

Stiles is trying to convince his dad to investigate Theo. He says the boy's family left town when Theo was nine or ten and that his older sister got into an accident when he was eight. The sheriff doesn't see why he should investigate Theo just because he is a werewolf. He points out that Stiles' best friend is a werewolf and he is dating a werecoyote. He says "When the flying monkeys come soaring through this station" he might pay attention to Stiles' concerns.

Stiles says he senses something different about his father but can't figure out exactly what it is.

Stiles pushes him again to do a full background check on Theo's family, the Raekens. The sheriff refuses, saying that just because he's the only one in law enforcement to know about the supernatural doesn't me he has to do something every time Stiles has a minor suspicion. Stiles realizes that his father is not the only lawman who knows about the supernatural. He turns to Deputy Parrish.

~~~

The background check was mostly fruitless Stiles explains to Malia as they arrive at school. He did find a speeding ticket signed by Theo's dad. Stiles says speeders are trying to get away from something, but Malia points out that he would have several tickets of his own if his father didn't get him out of them. Stiles admits he would have 17 speeding tickets without his father's intervention.

Malia says she understands why Stiles is worried and feels threatened because Theo is really hot with great hair and a perfect body. She offers to torture him for Stiles saying she believes she could take him. Stiles declines but says he has a plan with steps.

Get the story.

Verify the facts.

Find the piece that doesn't fit.

Catch him in the act.

Theo arrives at school, smiles, and waves at Stiles and Malia.

Malia still doesn't understand why Stiles is so suspicious. He says he remembers Theo and that this new guy isn't Theo.

First Day of School

Scott arrives at school is joined by Kira. They embrace and say it's going to be the best first day ever.

~~~

Mason has become obsessed with the Beserkers after his experience with Lydia and Sheriff Stilinski. He purchased an old German book for $200 which he says is totally worth it. Liam seems annoyed and uncomfortable with his obsession he lies and says he's never seen anything like the berserker illustration in the book.

"And then, there's this whole section about the Nagual. Have you ever heard of the name Tez-cat-" Mason tries to pronounce.

"Tezcatlipoca," Liz says as all three of them walk into Mr Yukimura's class.

"Yeah, have you heard of it?"

"Obviously-" Liz sees Liam's look and smiles a fake smile at Mason. "I love mythology," She says uncomfortable and quickly takes a seat.

The only other seat left is one between Mason and this other girl. Liam apparently knows this girl and does not want to sit beside her. He hesitates until the teacher forces him to sit down. He realizes then that Hayden has stuck bubble gum to his chair leaving a gooey pink mass on the seat of his pants.

~~~

Scott arrives in Advanced Placement Biology. Kira and Lydia pantomime their confusion about his presence in such a difficult class until Kira finally asks if he is in the right room. Scott is. He shows he is prepared by opening his heavily-highlighted and annotated AP Biology textbook. Reed and Lydia share a look of impression as the teacher, Mrs Finch, enters the room.

"Welcome to AP Biology! Let's see who's awake. Can somebody tell me what plasmids are?" she asks.

"Circular, self-replicating DNA molecules often used in cloning proteins" Lydia answers, seemingly without thinking.

"Nicely stated, Lydia. Now, can you tell me what vitamin is absorbed in the stomach via parietal cell production of a glycoprotein?" Lydia opens her mouth to answer but doesn't seem to know the answer. "Yes, Selene"

"B-12" Selene answers not really concentrated. She looks at the person next to her, Theo Raeken. The teacher asks Scott if he knew the answer. He says he didn't.

She then asks him about his number one college pick which he says is UC Davis. She says it is the best school on the west coast for biological and physical sciences. Kira seems surprised by Scott's answer. Mrs Finch says Scott is in the right class if that's what he wants.

She asks who else in the room believes they are in the right class and Theo raises his hand near the back of the room. She says there will be a test to help them determine if they should be in the class and they have two weeks to drop it if they decide they shouldn't be there.

~~~

Stiles enlists the aid of Scott to question Theo during free period.

~~~

"Look, I'm not saying I believe all of it a hundred per cent, but people around us seem to know things. Like Lydia and Cheryl? They know things" Mason drones on at Liam about his supernatural experience."Dude, it's the first day of school. Shouldn't you be thinking about other things, like... Like the soccer team?" Liam tries and Liz chuckles as she opens her locker."What do you think I'm going to do? Follow them out to the field and watch them practice while I pretend to study?" Liam shrugs."It's warm out. They're probably gonna be shirtless..." Mason sighs."I'll see you in physics" Liam and Liz both chuckle at Mason's adorableness. Liam has changed out of his gum-stained jeans and into his gym shorts. Hayden's locker is apparently right next to Liam's and Liz's is on his other side."Nice shorts" Hayden comments and Liz tries to hold in her laugh which results in it coming out as a snort."Yeah, thanks... You know, I was wondering if you were still pissed off about the sixth grade, but I guess you cleared that up..." Liam says and Liz frowns, not knowing what happened in the sixth grade."I'm not pissed off, Liam" She says and closes her locker. "I'm vengeful" She adds and leaves. Liam puts his head against his locker and Liz pats him on the back.

Daydreams About Night Things

Tracy walks to her locker. As she works the combination lock, she hears the crackle of electricity and a growling noise. She sees a looming shadow but once she opens her locker it all goes away and the hall is once more full of students. The light and her relief last for just a couple of seconds before the lights shut off in the hall and Tracy finds herself once again alone.

One of the lockers nearby begins oozing black liquid which pools on the floor just before the locker's latch opens by itself and one of the doctors (The Surgeon) climbs out. It crawls sideways along the lockers, defying gravity as it gets closer to her. She tries to convince herself that there is nothing there but the creature keeps coming. We hear Selene calling Tracy's name and the doctor phases out and reality phases back in. Selene puts an arm around the girl and leads her away from the locker which is now punctured by claw marks.

Theo's Backstory

Theo relates the story of how he got bitten to Scott and Stiles.

He claims he was skateboarding in an empty swimming pool, when he fell and his skateboard went flying into the air. He realized he never heard the board come back down and when he looked up, a man with red glowing eyes and claws was standing on the lip of the pool holding the board. He explains that this Alpha werewolf bit him on the side (the same side where Peter bit Scott in) and that by the time he figured out what was going on, he'd heard that the alpha that bit him had been killed by two of his betas who were also twins.

He urges Scott to listen to his pulse to tell if he's lying. Stiles points out that Theo could just know how to steady his pulse so he could lie without detection.

Stiles says Theo would lie because he's not who he claims to be so Theo relates a story about an asthma attack in 4th grade that sent him to the ER. Before leaving school for the hospital, Theo claims Scott comforted him about how easy the visit would be and how they would make him feel better with oxygen and an intravenous feed of Prednisone.

Stiles rolls his eyes at yet another Theo suck-up-to-Scott story but Scott seems to buy it.

Scott says they have to give people the benefit of the doubt sometimes. Stiles is convinced that he is right, that there is something "off" about Theo. Scott says Lydia is the psychic. Stiles points out that Lydia is not a psychic but a Banshee and that there's a difference.

Lydia, Selene and Parrish Try To Help

Lydia and her mother are discussing Tracy who is eavesdropping outside the classroom. Her mother is convinced the girl suffers from a sleep disorder but Lydia believes something more is going on and points to the fact that Tracy coughed up feathers. Her mom says night terrors have reportedly caused people to do a lot stranger things than eating their pillows. Lydia wants to take Tracy out of school and talk to her but Natalie refuses, saying that if the girl needs help they will get her professional help.

Lydia gets an idea about just which "professional" she can get to help.

Deputy Parrish checks the windows in Tracy's bedroom and finds them to be secure with no sign of forced entry. Lydia and Selene examine a number of drawings of blackbirds and other dark objects decorating the walls.

Parrish finds the skylight is not sealed shut as Tracy believed and on the roof outside he finds a mound of dead and bloodied blackbirds as well as some claw marks. Selene's facial expression seems to signal she can smell something happened outside.

~~~

In drivers' education class, Mr Yukimura is teaching Malia. She is heavy on the brakes causing the car to jerk. As she is driving, reality begins to phase out, replaced by a rapidly accelerating wooded scene and the sound of someone screaming. Malia pushes down on the gas accelerating toward a bus and a group of students. She catches herself and slams both feet on the breaks. She stops the car without crashing.

Mr. Yukimura can't get out of the car fast enough saying the lesson is over for the day and he sees room for improvement in her performance. On the track behind the car, several cones are knocked over and a mannequin crossing guard is lying on the pavement.

Evidence Mounts Against Theo

In the library, Stiles claims to have proof that Theo isn't who he claims to be. He's broken into the administrative office and found Theo's transfer form signed by his father. He says the signature doesn't match the signature of Mr. Raeken on the traffic ticket from eight years earlier.

He says the "garlands don't match. The undulations of the sinuous stroke are totally off." Elsewhere in the signature he finds a "Perfect example of the Criminal Tremor."

(As you might expect, all of the terms Stiles throws around in this scene are used in Handwriting Analysis. Garlands are the cup-like structures that connect letters in cursive handwriting. A "Sinuous Stroke" indicates the writer is hiding something or attempting to deceive while the "Criminal Tremor" is common in forgery because the person grips the pen too tightly in concentration while writing.)

Scott, Kira and Malia are unimpressed by Stiles evidence. He tries convincing them saying that if Theo's parents are psychotic killers then they shouldn't trust him. Malia points out that her parents are Peter Hale and the Desert Wolf both known as psychotic killers.

"Yeah, you don't even wanna know my biological father" Cheryl adds. Stiles seems to want to know who her biological father is but drops it. He is stymied by this, takes his evidence and walks away saying he doesn't need anyone. In the next scene, he's enlisted Liam and Cheryl to help him.

Supernatural Stakeout

"I can't do anything official right now, but I can come back after my shift tonight and watch the house for a couple hours" Parrish proposes.

"We'll keep you company" Selene proposes.

"I think I'll be okay"

"But this is your own time" Lydia counters.

"I wouldn't do it if I didn't think something strange was going on. I also owe you two" Parrish explains.

"For what?" Lydia asks with a smile on her face.

"Three weeks of digging through every piece of old literature and mythology, trying to figure out the 'something strange' going on with me" Parrish explains.

"But we never figured it out. I'll bring you coffee"

"Don't you have class tomorrow? Both of you?" Parrish asks.

"One class" Selene says with a big smile.

"How can you only have one class?" Parrish asks.

"We had enough credits to graduate last year, and we will bring you coffee at midnight if we want to" Lydia counters.

"Medium Americano. Black" Parrish gives in.

~~~

Stiles, Cheryl and Liam follow Theo to the woods. Liam says they've been watching him play video games for 3 hours before tracking him outside.

Liam remembers that he was supposed to meet Mason at school to work out and couldn't tell him what he was really up to because he's yet to explain that he is a werewolf. Stiles says he, Selene and Scott already gave him their permission to tell Mason and that he has already seen Stilinski blow up a berserker with a land mine so... Liam says it's not that easy but Stiles says he should because it is always better when they know.

Liam falls in a hole and notices, partially buried in the mud, a silver leaf-shaped necklace like the one seen earlier in Tracy's bedroom. Cheryl helps him out of the hole.

"You've been quiet" Liam points out.

"We're tracking someone down" Cheryl points out.

"Why do I feel like you suddenly hate me?"

"If I hated you, I would've buried you in that hole, not helped you out"

"That's good to know" Cheryl makes a shushing motion.

They catch up to Theo and find him casting a single lily off a bridge into the water below. Stiles has Liam use his ability to determine emotions from scent, chemosignals, and finds that Theo is grieving. Stiles realizes that this is where Theo's sister, who got lost in the woods and died of exposure.

Stiles, Cheryl and Liam beat a hasty retreat but Theo catches up with them.

"What are you guys doing?" Theo asks and Liam growls. Cheryl slightly pushes him behind her.

"Whoa! Why do I get the feeling this kid's tougher than he looks?" Theo asks and Cheryl smirks.

"Only when we let him off his leash," Stiles says and Cheryl hits him over the head.

"Stiles, we were in Little League together. Why are you so suspicious of me?" Theo asks.

"Because of these. One's a speeding ticket signed by your dad eight years ago. The other one's a signature on a transfer form to Beacon High. They're different" While Stiles says his words, Cheryl frowns and seems to start thinking about something.

"Huh. Yeah, they do look a little different"

"No, they're totally different-- signed by two different people"

"So, my dad's not my dad? Like, he's an imposter?"

"Yeah, something like that"

"Who do you think I am?"

"We don't know yet"

"Want me to give you a DNA sample or something...?"

"No. I don't have anything from fourth grade to match it to"

"You know, Stiles, I came back here for Scott... But I also came back for you. Someone like you. Someone who's willing to walk into the woods in the middle of the night to protect his friends. I don't have anyone like that, but Scott does. You all do. I know I'm in the right place. I'm meant to be here. I'm meant to be part of this pack"

~~~