Neighbourhood kids are smashing jack-o-lanterns on Halloween night. Suddenly a skein of five Demon Warriors appears out of the mist.

They pass the children by without a glance.

Isaac lies shaking on the floor in the room. He is freezing. Allison and her father find him and Chris Argent punches him until Isaac's werewolf side triggers and begins the healing process.

As Isaac explains about the Demon Warriors - they wore black, greenish-yellow eyes "like a firefly," and came out of the shadows - realization dawns on Chris' face. He asks Isaac and Allison to keep the attack quiet for 24 hours. Chris believes the creatures might have been after him. Allison says they should tell Selene but Chris ask for 24 again, they agree.

He goes to his room and retrieves a wooden box, inside we see one of the Demon's broken into pieces.

~~~

"So when did you get there?" Agent McCall attempts to question Stiles, Selene, Lydia, and Kira about the incident at the power plant.

"At the same time" Stiles answers.

"At the same time as who?"

"Same time as me" Selene answers while Stiles points at her.

"By coincidence?"

"What do you mean coincidence?" Stiles asks, he and Selene having both their eyebrows furrowed.

"That's what I'm asking you. The two of you arrived at the same time. Was that coincidence?"

"Are you asking me?" Selene asks.

"I think he's asking me," Stiles says.

"I think he's asking both of you" Lydia replies.

"Okay, let me answer the questions," Agent McCall says. Both Selene and Stiles raise their eyebrows. "Let me ask the questions" they point at him signalling that's better. "Just so I have this absolutely clear. Barrow was hiding in the chemistry closet at the school. Someone left him a coded message on the blackboard, telling him to kill Kira. Then Barrow took Kira to a power substation and tied her up with the intent of electrocuting her, which blacked out the entire town?"

"Sounds about right," Selene and Stiles say at the same time.

"How did you know he would take her to the power substation?"

"Well, cause he was an electrical engineer. So where else would he take her?" Stiles explains.

"That's one hell of a deduction, Stiles"

"Yeah, what can I say? I take after my pops, he's in law-enforcement" and said pops snorts. Which he hides with fake coughs.

"We made a good guess" Selene then explains.

"You believe this?"

"To be honest, I haven't believed a word Stiles has said since he learned how to speak. But I think, these kids found themselves at the right place, at the right time and that girl sitting there is very lucky for it" Sheriff Stilinski explains.

"Kira? Is that how you remember it?"

"Yes... Can I get my phone back now?" Kira answers and asks.

"Sorry, but no"

~~~

In her room, Kira lights a candle. She then takes a selfie in the mirror. The image shows she is surrounded by, what appears to be, flames in the form of a fox warrior.

~~~

The power is still out the next day at school. Class is still in session though as Coach reminds everyone via bullhorn. Stiles knocks his keys from his locker onto the floor. We can see he has a green aluminum bottle opener as a key chain. He notices one specific key, staring at it until Scott arrives. He stops Scott from walking right up to Kira suggesting that he steer clear until they know that she isn't "another psychotic monster that's going to start murdering everybody." Stiles explained everything to Scott through text.

Scott wonders if Kira might be like him in a supernatural sense, Stiles reminds him of her trick with the electricity saying she's definitely not like Scott. Stiles again seems perplexed by that key on his ring.

~~~

In the locker room, Danny is on his cellphone. Apparently the power outage means the Halloween blacklight party he'd planned will have to be cancelled. Ethan overhears and asks him if he needs help finding a new venue. Danny says no place in town has power so the party is canceled.

Aiden makes fun of his brother's attempt to engage Danny but Ethan points out that Scott doesn't care about power, he cares about people. He goes on to explain that if they ever want to be a part of Scott and Selene's wolf pack then they need to start by acting like humans at school.

Mrs Martin (Lydia's mom) is substitute teaching for the recently deceased Harris. She jokes with Lydia that since she's not been in front of a classroom in 5 years she would really appreciate it if her daughter wouldn't embarrass her. Lydia quips back that her mother should have thought of that before wearing "those shoes."

Later, as Aiden is trying to flirt with Lydia, she is obviously uncomfortable. She explains that she helped save a person's life and feels good about that. She says when she looks at Aiden all she can think about is that he killed people and that doesn't just make him a "bad boy" it makes him a "bad guy" and she doesn't want to be with the bad guys. This prompts Aiden to approach Danny and offer him a place for the party.

~~~

Derek leaves his loft for unknown reasons.

~~~

Kira is eating lunch by herself in a school hallway. Scott joins her on the floor. Kira immediately says she doesn't "want to talk about it" but when Scott starts to talk about a pre-calculus test on "Friday" instead, she asks him to take a picture of her so she can show him the effects flash photography has on her face.

The picture shows the flames outlining her body. She explains that the strange happenings started a "couple of months" ago and she doesn't know what causes it. She says she has to get hold of her phone to erase the pictures Barrow snapped at the substation. Scott immediately volunteers to help.

~~~

Derek returns to the parking lot right outside his apartment later that night. He is ambushed by three trick-or-treaters, a devil, a pirate and a vampire. The kids are on edge as Derek slowly reaches into his SUV and pulls out a large variety bag of M&M/Mars fun sized candy. He drops a piece in each kid's bag. They stand staring at him until he flashes his eyes and, with a roar, bares his fangs. The display sends them screaming into the night.

As Derek turns back to the SUV he is surrounded by the five Demon Warriors.

~~~

Aiden and Ethan set up a gas powered generator outside Derek's big loft window. The power comes on and they test the black light fixture they attached to one of the support posts.

~~~

Outside the Sheriff's Station, Stiles is waiting in his jeep when Kira and Scott arrive on his dirt bike. Stiles has key cards that will give them access to the station and several of the offices inside, including the evidence room. He explains that he cloned the cards using an RFID emulator.

He points out that, since his father is already under investigation by the FBI, he can't help them if they get caught & will run at the sight of any official or officer.

Kira is worried that Scott told Stiles why she wanted the phone. Scott says he said there were pictures she didn't want anyone to see, naked pictures of herself. Kira is cool with this explanation saying it was a "good idea."

Inside they find Kira's phone but it is dead and with no power there is no obvious way to charge it. She wants to just take the phone but Scott knows that would cause more trouble for everyone. He then notices a laptop on the desk. Kira finds a charging cable in a desk drawer and they turn on the computer to charge the phone from its battery. When the computer screen flicks on, there is a picture of Scott as a very young child with his father, Agent McCall. He realizes that this is his father's laptop and has a little moment of wistfulness as he remembers that period of his life.

Stiles is still fascinated by the extra key on his key ring.

Meanwhile, Kira's phone takes forever to get enough charge to start.

Agent McCall pulls up outside and Stiles, unable to get Scott on his phone, runs inside to head him off. He stops Scott's dad, attempting to stall him outside the evidence room with the somewhat obvious theory that whoever left the message for Barrow in the chemistry classroom may be someone at the school.

Kira's phone finally charges.

McCall says it's a good theory and one they are already pursuing. Turns out, Stiles' father was the one who came up with it. The agent calls it "his one useful suggestion." Stiles gets in McCall's face. He says that the attitude the agent has toward Sheriff Stilinski may be all dressed up in "professional disapproval" but Stiles knows the real reason McCall doesn't like his father. It's because "he knows something that you don't want him to know." The agent tries to shake off the revelation but Stiles continues "and guess what. I know it too."

Kira and Scott have escaped undetected. She seems very excited about the adventure. Scott invites Kira to the black light party. & she gladly agrees.

~~~

Isaac opens the door to the loft revealing a group of scantily clad, glow-in-the-dark teens dancing to The Bloody Beetroots. He turns to Selene, Cheryl, Allison and Reed and says "Derek can never know about this."

~~~

Ethan is sure to remind Danny that he is responsible for pulling the party together. He then rips Danny's shirt off to facilitate glow-in-the-dark body painting. Someone calls that they've run out of ice and Ethan leaves to find some more. While the artist paints Danny, Demon Warriors begin to appear behind him. Catching a glimpse in his peripheral vision, he turns but the figure is gone.

~~~

Ethan enters a storeroom to grab some ice. The incandescent light bulb flickers and goes out. He twists the bulb and it comes back on briefly but goes out again. This happens a few times until the Demon Warriors appear and surround him.

~~~

Stiles, Scott, and Kira arrive at the party. Stiles is now obsessing about the key, explaining to Scott that he's asked his father if he put it there but he says he didn't. Stiles knows it is not his key. Scott is prepared to leave the party until they figure out the mystery of the key but, at that moment, Caitlin walks up to Stiles and kisses him. The smooch leaves a glowing orange lip-print on his cheek. Stiles now does not want to leave the party and goes off in pursuit of Caitlin.

Kira gets jostled by the crowd. Scott takes her hand and pulls her close to him. Then he spots Allison standing at the bar. Kira sees him see her and releases his hand and backs away into the crowd.

Scott and Allison exchange half-smiles, an acknowledgement that what they had is over. Scott realizes that he's lost Kira and begins to scan the room with his werewolf vision. When he spots her he sees the outline of a fox in the flames surrounding her entire body.

Stiles catches up to Caitlin and after some chit chat, realizes her connection to the sacrifices, her girlfriend was one of the virgins killed. Caitlin seems unfazed by girlfriend's death, says she's really drunk and takes Stiles to the dance floor.

~~~

Aiden runs up to Lydia wearing a set of bright orange false fangs. He growls at her. She is not amused. He says they're not as good as the real ones. Lydia counters that they're also not as "lethal." Aiden says he deserves everything Lydia says about him but adds that he helped set up the party as if that should earn him a bit of redemption. Lydia is unimpressed and says if she'd wanted to go to a rave she would get in a time machine and go back to the 90s. She walks away. Aiden is angry, showing his real fangs and glowing eyes.

~~~

"I know something's wrong," Selene says to Isaac as they stand at the sideline. "What happened?"

"Nothing" Isaac replies

"Liar"

"Were you listening t my heart?"

"Of course not, I trust you, Isaac. I just know when you're lying... I know you"

"I'm not the only one who has something on my mind. What's wrong?"

"Nothing"

"Are you mad at me?"

"I'm not mad"

"No?"

"No"

"Okay"

"I'm frustrated"

"Sexually?" Selene turns to Isaac with a raised eyebrow. They both chuckle. She looks at him and then walks past him, brushing against him. Isaac rolls his eyes as he follows the girl.

"Can I borrow one?" Selene asks one of the paint artists and takes off her shirt. "You wanna talk about secrets or you wanna paint my body?"

"I wanna paint your body"

~~~

Lydia stands alone and sums up the party with a series of "ly" words. Seeing Isaac and Selene she says "Finally." Stiles is dancing all crazy which earns him an "Awkwardly." She then notices Aiden sandwiched between two grinding girls and says "Predictably."

Lydia hears something, a light growling and popping sound. She scans the party but sees nothing at first. Then the Demon Warriors begin to flicker in and out of existence. She calls out for Scott but can't be heard over the loud music. She makes her way outside onto a wide patio-like ledge beyond the loft's giant window. There she catches her breath. The popping sound returns and one of the Demon Warriors rises up through the concrete. She turns to scream but another warrior is there and snatches the sound from her mouth with his hand. It then places a hand on the left side of her face and its eyes begin to glow.

~~~

Danny mistakes Aiden for his brother. Both are looking for Ethan because he's been missing for a "half an hour." Aiden goes off on his own looking worried. Danny follows.

~~~

Caitlin retrieves two bottled beers and returns to Stiles on the spiral staircase. When Stiles removes his key chain to use the bottle opener, Caitlin notices that one of his keys, THE KEY, is covered with phosphors.

Caitlin wants to make out. She says she likes girls and boys and asks if Stiles likes boys too. He doesn't answer and looks uncomfortable. He is obsessed by the mystery key and keeps interrupting their kissing with questions. When Caitlin explains that the phosphors might have come from being around chemicals, Stiles jumps up to leave. Before he goes he gives Caitlin a full bottle of water and tells her to "drink that whole thing."

~~~

Kira and Scott are up on the roof, just above the loft's skylight. Scott has paint on his face and when he can't get it himself Kira "moms" him. That is, she licks her thumb and uses it to wipe the paint from his face. They laugh about the "momming" before turning to more serious matters. Kira is surprised that Scott didn't run away screaming when he saw her picture. She says the flames look like a "demon from hell" to her. Scott says he saw something different, like armor protecting her. He says it looks like a fox.

~~~

Selene and Isaac dance and come close to kissing but don't because Selene notices something on his neck.

"What? What's wrong?" Isaac asks.

"Something on your head. It's behind your ear" Selene explains. They rush to the mirror in the storeroom and discover what looks to be a backwards number 5 branded into Isaac's neck.

"It looks like the number five" Isaac whispers.

"Isaac"

"Yeah?"

"Why do you have a Japanese kanji on your head?"

"A what?"

"A Japanese symbol. This one means self or oneself. Why do you have it on your head? It didn't just appear" They hear Ethan groaning and Isaac breaks his arm to trigger his werewolf healing. Ethan's eyes flash blue and Selene notices he has the same mark on his neck.

~~~

Outside the giant window, Danny finds Lydia, barely conscious and shivering, he calls to Aiden for help. Danny says Lydia is practically "hypothermic." They carry her inside and place her beside a heating vent. Danny goes to look for a blanket and Lydia tells Aiden that "they came out of the dark."

~~~

Derek awakes on the pavement below. He jumps to his feet and growls in anger. High up on the roof, Scott hears the growl and recognizes that it is Derek.

~~~

Inside the party, Derek approaches the DJ table. A bouncer attempts to stop him but Derek tosses him aside and overturns the table. The music stops. He drops his voice into the "werewolf range" and bellows "Get out!" After a brief moment of disbelief, the crowd runs for the exits.

Aiden sends Danny away with Lydia. While everyone is running out the Demon Warriors become visible. Selene and Isaac run into the room carrying Ethan. Selene sees the Warriors and her eyes become big. All of the Warriors turn to Aiden and Selene growls in response. She removes Ethan's arm from around her and starts circling a Warrior.

"Anata ni wa bijinesu ga arimasen (You have no business here)" Selene says in Japanese and all Warriors turn to her. They pull out swords from their chest and Selene growls, showing her fangs and letting her eyes become red. All of the other werewolves also jump into the fight. Derek snaps one of their necks and it just puts its self back in place.

"What the hell are they?!" Scott yells after just nearly escaping a hit from one of the Warriors.

"I don't know" Selene answers as she pulls out her own sword. One of them pushes Scott and he flies backwards. "But they're stronger than I thought" Before they know Isaac, Scott and Derek are on the ground groaning. That's when Selene realises they didn't kill Isaac, they marked him. The Warriors look at her and she drops her sword. They search her soul and mark her like the others. She starts to lose consciousness and Isaac quickly gets to his feet. He catches her before she falls to the ground. The Warriors turn to Aiden again, search and mark him. Then they turn to Scott on the ground, who's attention was with Selene.

"Scott! Look out!" Derek yells and Scott quickly gets up. He lets his eyes glow and fangs come out. He looks back at Kira, who looks scared out her mind of the Warriors, not Scott. Isaac triggered Selene's healing and she quickly gets up. That's when the light begins to fall through the windows and the Warriors disappear in black smoke.

"What the hell were those things?" Scott asks.

"Your dad's 24 hours are up," Isaac says to Allison.

~~~

Chris Argent stumbles into his apartment badly injured and collapses on the floor. His phone is ringing, it's Allison.

~~~

At School, Stiles finds THE KEY fits the chemical storage room where Barrow hid and performed surgery on himself. Stiles makes his way to the blackboard where the numbers and their chemical counterparts still spell K I Ra. He grabs a piece of chalk and writes the same numbers on the board. The handwriting is almost identical to the original.