Jackson gets a text message during class. He leaves school and heads for somewhere in the warehouse district. The rave is selling tickets, and Matt is there. He asks Jackson if he's there to punch him again, but Jackson is acting under the control of his master and doesn't answer. Matt offers to let him go ahead of him in line. Scott peers around a corner, keeping an eye on Jackson.
Sheriff Stilinski takes a bite of dinner and makes a face. "Oh what the hell is this?" "Veggie burger!" Stiles chimes. They're having a healthy dinner, and Stiles holds up his salad. The Sheriff opens what he expects to be fries and finds celery and carrots. "Why are you trying to ruin my life?" "I'm trying to extend your life." Stiles asks his dad to tell him what he found, and the Sheriff says he's not sharing confidential information with a teenager. Stiles notices a large case board on the wall behind him and asks if that's it. Stiles takes a closer look, and his dad tells him to avert his eyes. Eventually he relents and tells Stiles that he did find something in common with all three kanima murders. "One's an incident, two's a coincidence--" "Three's a pattern," Stiles finishes.
The mechanic, Sean, and Jessica were all 24. The only one that didn't fit the pattern was Mr. Lahey. The Sheriff thought that might mean it was not connected, or that the ages were a coincidence. But then he found that Isaac had an older brother named Camden. If Camden were alive, he'd be 24, but he died in combat.
Back at the rave ticket booth, Scott asks Matt how much tickets are. They're $75, and then Scott asks to borrow $75. Matt gives him a look like he's an idiot, and Scott goes to the back of the line.
Stiles asks his father if thought of same age meaning same high school class. He hadn't and says that he only got Lahey's file two hours ago. Stiles is incensed. They go with the same class idea and grab Beacon Hills High School yearbooks. They were all class of 2006. The Sheriff suggests that they could have had the same classes together. Then he flips open a file and sees a photo of Mr. Harris and says they could have had the same teacher. He tells Stiles to put faces to everyone who was in Harris's 2006 Chemistry class. If the killer isn't done, then someone in that class could be next. The camera stops on a photo of Kara Simmons, who is currently selling tickets for the rave. Jackson steps up to the window and holds up one finger to indicate the number of tickets he wants. When she hands him the ticket, he makes sure that their fingers touch. Jackson freaks her out so much with his staring that Kara has her people activate the elevator that they're selling tickets out of.
An EMT lets Chris Argent and Allison into the morgue a little past 7:30pm. Chris reads their toe tags. He was looking for Sean, and he explains to Allison that Gerard said Sean was killed by a shapeshifter that no one has seen for centuries. He tells her it's called a kanima. He then says that Jessica was smothered to death and they think the kanima's master did it. So there are two killers, one human and one not. Chris says that when he learned about their family, he asked his father, "Why us? He quoted me Winston Churchill. 'The price of greatness is responsibility.'" Allison looks distressed. Chris, however, thinks that it's the truth they know about the world that makes them responsible. Their knowledge gives them the power to defend people who can't defend themselves. Allison responds that she gets that this isn't a lecture but an interrogation. He tells her that depends on what she knows. They saw the video of the library being destroyed and know that Allison is trying to protect her friends, but what she knows makes her responsible for the people that are dying. He pulls away the sheet on Jessica and tells her that she's responsible for that death. She asks what he wants her to tell him. "Anything you know. Anything that can lead us to answering the one question that might mean everything. Who controls the kanima?"
Scott lets Derek and Isaac into the Animal Clinic. Scott asks what Isaac is doing there. "I don't trust him." "Yeah, well, he doesn't trust you either," Isaac replies. Derek says, "Derek really doesn't care!" Derek asks if Dr. Deaton is going to help, and Deaton replies that that depends on whether they're going kill Jackson or save him. Scott answers "Save him" and Derek answers "Kill him." Scott insists on saving him, and Derek relents. Deaton brings them into the back room and sets out a tray of bottles. Isaac goes to pick one up, but Derek grabs his wrist to stop him and tells him to watch what he touches. As Deaton checks through the bottles, Isaac leans on the table and asks him if he's some kind of witch. "No, I'm a veterinarian." Deaton tells them he doesn't have anything that would be an effective defense against a paralytic toxins. Derek tells him that they're open to suggestions, and Isaac asks about an effective offense.
Derek tells him that he slashed its throat pretty deeply and Chris emptied a clip into it and it just got up again both times. Deaton asks if it's shown any weaknesses, and Derek tells him that it wouldn't go near water. Deaton asks if that's true of Jackson, and Scott tells him that Jackson is captain of the swim team. Deaton says that they're trying to catch two people: a puppet and a puppeteer. He holds a medallion up and then puts it on the table. They are also aware that the kanima killed Sean but the puppeteer killed Jessica. Deaton asks why the human had to kill the wife. Scott suggests that Jackson couldn't do it because his mom was killed while pregnant too, and was possibly murdered. Isaac suggests that it could be part of the rules. The kanima kills murderers. If it killed Jessica, then the baby would die too. Scott asks if that means Mr. Lahey was a murderer. Isaac woudln't be surprised if that were the case. Deaton then suggests that the kanima's fear of water isn't from Jackson but from the master. "What if something that affects the kanima also affects its master?" He takes out a jar of mountain ash and pours a circle around the medallion.
Friday morning, Scott and Stiles arrive at school. Matt is chaining up his bike. Scott asks if there's any other way to get tickets. Stiles tells him that there's only one way and it's a secret. Matt stops them to ask if they know why no one is getting suspended after the library incident. Stiles tells him to forget about it because nobody got hurt. Matt got a concussion. "Well nobody got seriously hurt." "I was in the ER for six hours." Stiles explains how low on their list of priorities his injury is, and Scott steps in to ask Matt if he's okay. Matt tells Scott that he found tickets available online and that they should keep trying. They believe that the kanima's master will be on hand to witness the next murder because the kanima didn't do the job correctly last time.
Coach Finstock comes into the boys locker room and demands to know where Jackson is and why he missed practice. Stiles says that he hasn't seen him since the last time he saw him. "And when was that?" "The last time I saw him? Definitely the time I saw him last." The Coach tells Danny to tell Jackson that he's not allowed to miss practice this close to the championship. Scott and Stiles had been trying to get tickets out of Danny. Danny says he's only got two. Stiles asks him if he has a date yet, and Danny growls at him that he's working on it. Stiles offers that Danny just give them the tickets and then devote his life to abstinence. Isaac has been listening, and he grabs Scott and Stiles by the shoulders, giving Danny a chance to get away. "How do you two losers even survive?" Isaac asks. Scott claims that no one is selling any tickets. They see a ticket exchange take place, and Isaac pats Stiles on the chest as he tells them to wait right there. Isaac beats up another student for the tickets and then hands them to Scott and Stiles. "Enjoy the show!"
Allison is waiting in the Chemistry lab for Scott, extremely agitated. She tells Scott that her dad knows about the last two murders and that there are two killers. Scott says it's fine and tells her that he's more worried about her mom. He says that when he was called to the office it was because Victoria wanted to talk to him and asked him really specific questions. There were pencils being sharpened. Scott thinks they need to be seen dating other people. Allison admits that she said yes to going out with Matt. "Oh, great! That's perfect! Go out with him!" Scott tells her to make a big deal out of it in front of her mom and even kiss Matt if she has to. Allison asks if she should really kiss him. Scott wants to know what a real kiss is, so Allison demonstrates. He asks that she not quite do that. Allison gets a distant look on her face but won't tell Scott what she's thinking. As she leaves, Scott says "I love you," and Allison responds, "You, too." Victoria sees them in the lab and is fit to murder.
Deaton gives Scott a needle full of ketamine to knock Jackson out. It's the same thing they use on the dogs. Then he gives them some mountain ash and says this part is for Stiles and only him. Stiles is a bit put off by the amount of pressure. He has to make a line of mountain ash around the whole building and it will trap supernatural creatures inside. "Think of it like gunpowder. It's just powder until a spark ignites it. You need to be that spark, Stiles." "If you mean light myself on fire, I don't think I'm up for that," Stiles replies. Deaton smiles and tries again, explaining that the spark is a force of will. Deaton tells him that if it's going to work, he has to believe it.
Meanwhile, the Argents and their hunters gear up. Chris tells them that the party is in a warehouse just inside the industrial sector. Allison is going to go into the party and determine Jackson's location. When Jackson is as far from the crowd as possible, she'll signal her father. "There will be no collateral damage tonight!" Chris dismisses Allison. When she's gone, Gerard points out that Allison is under the impression that they are planning a trap and not a kill.
Sheriff Stilinski gets home just as Stiles is running out. Stiles notices his father's mood and asks him what's wrong. Then he asks him where his gun is. "I left it at the station along with my badge." Stiles is stunned. His father tells him that they'll talk about it later. Stiles tries to talk about it now, but his dad tells him not to worry. Stiles insists. "It was decided that the son of the police chief stealing police property and having a restraining order filed against him by one of the town's most respected attorneys did not reflect well on the county." Stiles realizes that he got his dad fired. The Sheriff tries to tell him that it's a temporary leave of absence, but they didn't say that when they let him go. He again tells Stiles that they're going to be fine. Stiles asks him why he isn't angry at him. "I don't know. Maybe I just don't want to feel any worse than I already do by having to yell at my son." Stiles is on the verge of tears.
Scott and Stiles arrive at the warehouse, and Scott asks Stiles if he's okay. He didn't talk on the way there. Stiles gets his bag of mountain ash from the back of the car and declares that this plan sucks. Scott notices something in the air and runs off.
Isaac and Erica head into the rave. Matt and Allison are there as well, with Scott watching close by. Allison takes a second to go talk to Scott. Scott didn't realize that she would be there and tells her that they have a plan. She says that Chris and Gerard are going to be there too. Scott demands to know what she told them, and she admits to telling them everything. Scott doesn't know what to do because their plan is going to be ruined now. Allison says she can fix it if he tells her what to do. He tells her to stay out of the way.
Meanwhile Stiles is outside creating the ring of ash and the hunters all arrive. "Be careful, gentlemen. Something wicked this way comes," Gerard villains.
Scott gives the ketamine needle to Isaac because he now has to make sure that Chris doesn't ruin their plan. Scott explains to him where to do the injection. "Be careful." Isaac laughs. "I doubt I'll even slightly hurt him." "No, I mean you. I don't want you to get hurt." Isaac gives Scott a long look, because that's interesting news from someone who a couple of days ago declared he didn't trust him.
Derek and Boyd confront the hunters outside. "Derek, back off." "Back off? That's really all you've got? I gotta be honest, Chris, I was really expecting more from the big bad veteran werewolf hunter." Chris smirks at him. "How about, didn't anyone ever tell you not to bring claws to a gun fight?" The hunters all take aim, and Boyd gets rattled. "That one sounded pretty good." Derek gives him a look. Inside, Jackson starts making his way toward Kara. The hunters open fire, and Derek and Boyd have to take shelter behind a Dumpster. Erica finds Jackson and distracts him by touching his neck and starting to dance with him. Isaac joins in, and it's the three of them dancing. The boys kiss Erica and eye each other. Stiles is still making his way around the building. Boyd and Derek get an opening and start fighting the hunters. Two hunters hit Derek with tasers, but he grabs the cords and uses them to throw the men into each other. Isaac gets the needle ready, but before he can strike, Jackson stabs them both with his claws. "He belongs to me," the master says through Jackson. Stiles gets close to the end, but he's running out of ash. He pours what's left in his hand and looks at the 50 feet he has left to go. Isaac manages to get the needle and attack Jackson from behind. He knocks him out and hauls him away.
Scott comes out of the warehouse checking his phone. Victoria Argent plows into him with her car. Stiles calls Scott to tell him that he's out of ash. He standing alone with gun fire and Werewolf everywhere and a handful of magic fairy dust, "And I don't have enough." He has to imagine it working, and just then sees a car with the Einstein quote that imagination is more important the knowledge. With no other option, he decides to believe and lets the ash fall through his fingers, walking with his eyes closed. When the ash runs out, the circle is complete. Stiles dances around and cheers.
Scott wakes up in a warehouse with Victoria Argent. She has a vaporizer and complains about how kids these days get them free with their medicinal marijuana cards. She sniffs some wolfsbane and claims it's one of her favorites. Scott asks her what she's doing. "Isn't it obvious. I'm killing you."
Stiles arrives at the location where Erica and Isaac have taken Jackson. He asks if Jackson is okay. Isaac gets out his claws and attempts to slash Jackson, but Jackson catches his arm and twists it without seeming to be conscious. Isaac escapes, holding his hurt wrist. He complains that the ketamine was supposed to put Jackson out. Stiles figures this is all they're going to get. Jackson's eyes open and he starts talking. "I'm here. I'm right here with you."
Victoria wafts the wolfsbane toward Scott explaining that it will look like he died of an asthma attack. Scott wolfs out and coughs, but he has no strength to save himself.
Allison texts her father that she can't find Jackson. Matt asks her if she wants to move closer to the DJ. They run into Mr. Harris. He tells them that his date is 21.
Chris is still okay. Derek and Boyd are hiding from him, and Boyd says that he isn't healing. Derek tells him that the bullets are laced with wolfsbane and tells him to leave. Boyd asks about him, but Derek says that he has to find Scott. Boyd eventually runs.
Stiles kneels down to talk to Jackson. "Jackson is that you?" "Us. We're all here." Stiles questions the master about the people he's killed. The master claims they've all deserved it. Stiles asks who all these people have murdered, and the master replies, "Me." This freaks even the Werewolf out, who back up.
Gerard finds Stiles's line of mountain ash but does not break it.
Matt can tell that Allison isn't having a good time and asks her about it. She says she feels like she's just making one mistake after another. He kisses her, and she pulls away. He apologizes. Allison leaves to go make a call. Jackson starts changing, and Stiles says they need to give him more ketamine. Isaac holds up the empty bottle. Jackson stands, and they all run from the room and throw themselves against the door to keep it closed. The kanima just bursts through the wall. Kara leaves the DJ station, and the kanima stabs her through the throat.
Stiles come out of the rave. Derek runs up next to him, and Stiles tells him that they lost Jackson inside. Isaac and Erica come up, but they can't leave because of the barrier. Stiles realizes the barrier works and is extremely proud of himself.
Victoria monologues at Scott, telling him that omegas never survive. "I've heard the cry of an omega. It's a miserable sound." Scott forces out the words "I'm not alone." He manages to howl, and Derek hears him. Derek tells Stiles to break the barrier, and Stiles refuses at first. Derek insists that Scott is dying, and Stiles asks him how he knows. Panicked, Derek orders him to break the barrier. Stiles kneels down and flicks a gap in the ash. Derek takes off to find Scott, and Stiles looks defeated at having his one accomplishment ruined after so short a time. Scott asks Victoria to tell Allison that he's sorry. Derek bursts into the room with Scott and is disoriented by the wolfsbane in the air. Victoria stabs him in the back. They grapple, and she manages to throw him across the room. She runs away. Derek hauls Scott up and out of the room.
Allison runs out of the rave, only to be stopped by Gerard. She tells him that none of it worked, but he's not so sure about that.
Later, David Whittemore and Sheriff Stilinski are at the crime scene. David asks him if he thinks it's a good idea being there. The Sheriff responds that he just wanted to know her name. David tells him it was Kara. The Sheriff checks his list of names, and hers isn't on it.
Dr. Deaton takes care of Scott while Derek watches. Derek looks a little ill from the wolfsbane, while Scott is completely unconscious. Derek thanks Deaton for his help.
Ms. Morell is waiting for Dr. Deaton in the office. "I can't decide if I admire your sentimentality or despise it." He says that if he wants guidance, he'll make an appointment. She asks if he's really going to leave everything up to some kids, and then asks if he plans to tell them what's coming. He thinks they have enough to worry about at the moment.
Victoria finds Chris outside the warehouse and falls into his arms. Derek bit her during the fight. They both know that it means she's dead.