Previously on Teen Wolf, Danny and Ethan and Aidan threw a Halloween rave at Derek Hale's Home for Wayward Werepups that was busted up by some Death Eaters, growling and tattooing every supernatural person behind the ear. Allison spent the whole time trying to get Isaac to stop talking about Scott and grope her. Scott spent the whole time trying to unravel the glowing mystery of Kira (not a euphemism). Lydia spent the whole time being just super unimpressed. And Stiles split his time between deciding if he's bisexual and deciding if he ordered the execution of Scott's new girlfriend.

Meet the young Chris Argent

Chris Argent was somehow even hotter when he was a teenage werewolf hunter. I'm not even kidding. He's every inch a full ten right now, as a grown man, but when he was in college, dating crazy Victoria with those eyeballs and doing Gerard's bidding ("intercept that shipment of MOUNTAIN ASSSSHH!"), he looked like some kind of mythological god. Back then, when he was defying nature with his face even more than he is right now, he did some arms dealing in Japan, which is where he first encountered the Death Eaters. They killed all the guys he was trying to sell WMDs to, except for one: Katashi Silverfinger. Chris saved his life. It was all very bloody.

Katashi Silverfinger is hanging out in Beacon Hills these days (apparently and of course), so that's where Chris was on Halloween night, tracking him and looking for answers. Unfortunately, when a shady group of demon ninjas whose faces are made of literal darkness try to murder you in your youth, you get a little squirrelly about taking meetings with any old Joe, so Katashi Silverfinger wouldn't take Chris' calls. So Chris decides to recruit Allion and Isaac to help him meet up with the guy and sell him some weapons... because that worked out so well for him last time.

Kira returns home after a night of being hunted like a wild beast by glowy-eyed satans and boy is she ever blissed out. The reason why is that Scott drove her home on the back of his motorbike and let her touch his fully transformed werewolf face. The music wants you to believe this is the first time such a kindness has been bestowed upon young master Scott, but we've see both Allison and Stiles caress his lupine noggin in the waning sunlight loads of times. But Kira feels real happy about it. Finally, she can date someone who also belongs in a bestiary.

On the way to school, Aidan and Ethan cuddle up Scott in a motorcycle sandwich and tell tell him that they plan to do it, quote, all day and all night. He needs some space from their identical, overbearing embrace. For one thing, he's pretty sure the Death Eaters are after Kira and not him, and he doesn't want to blow her cover. And for another, he needs to explain things to Stiles without their jealous eyeballs following his every move. He calls himself "The True Alpha," a phrase that never stops delighting me when spoken aloud, and tells them not to eavesdrop on him.

Aaaaaand it's a good thing because Stiles is a mess this morning. He drags Scott into the chemistry classroom to show him his handwriting on the blackboard calling for a hit on Kira. But it's not there anymore. So he drags him over to the supply closet to show him he has a key to the room where Barrow got the chemicals to make his bomb. But he doesn't have that key anymore. OK, OK, fine, but the bomb was made of bolts and nuts and screws, right, and that's exactly what Stiles and Scott used in the birthday fun-bomb they made for Coach Finstock. Stiles keeps saying "phosphors, phosphors" and twitching, so Scott puts a hand on his shoulder and goes, "Dude, listen. You're my super-smart human sidekick with an angelic face and a blossoming curiosity about the same sex. When has a person like you ever turned evil?" When indeed.

Not attending school today are Isaac and Allison, both of whom have accompanied Chris to Silverfinger's lair to sell him an antique pistol — but only as a ruse! Chris really just wants Isaac to entertain Silverfinger so he and Alison can sneak inside and get him to do an infodump about Japanese monster mythology! Isaac is very nervous, firstly because he doesn't feel comfortable in the suit Chris is making him wear and secondly because his main mode of distraction is usually just, like, "This is my face. Stare at it as long as you want." Alison gives him a boner to help him concentrate on their plan, which seems a little counter-intuitive to me. For real, she kisses him and guides his hand into groping her ass and then she's like, "How do you feel now?" And he's like, "I've got a raging erection! Let's do this!"

Stiles goes to the hospital to see a doctor, but there are none. Never have been any. Never gonna be any. The hospital has one employee and it is Melissa McCall. She checks in Stiles, takes some notes on his symptoms — "insomnia, blackouts, hallucinations, panic attacks, inability to read, occasional first degree murder attempts" — then shoots him up with NyQuil to help him get some rest. The saddest thing you have ever heard is Stiles saying, "Thanks, Mom" when she pulls the covers up around his chin.

Melissa seems to remember checking in another patient with these exact symptoms nearly a decade ago, so she goes rifling through the file room and finds what she's looking for. Yep. Insomnia, blackouts, hallucinations, the whole thing. This patient died from it. This patient was Claudia Stilinski. Melissa, hilariously, shrugs and sighs and re-shelves the file, all, "Oh, well."

Scott decides the best way to keep Kira safe is ditch the protection of the twin werewolves who have sworn fealty to him and hang out with her by himself in his bedroom until it gets dark. Kira isn't opposed to the plan. In fact, it gives her time to explain to Scott that she thinks she's a firefox, a kitsune, and even though firefoxes' oldest enemies are wolves and Internet Explorers, she thinks making out with Scott is a fine idea. Of course Agent McCall foxblocks their plans, busting up into the house uninvited to accuse Scott and Kira of busting up into his office uninvited. Scott's just working himself into a zinger tornado — "You donated one sperm to my existence; you are not my father" — when Melissa comes in to set the MOUNTAIN ASSSSHHH security system in place before the sun goes down.

And darn it, she just misses the deadline! The Death Eaters apparate into the house and stare and stare and hiss and bare their teeth and glow their eyes and hiss some more. Agent McCall is all, "The hell you say, intruders!" and is promptly stabbed in the chest with a katana. Melissa drags his limp body out of the way as the twins burst through the windows and Derek Hale comes gliding through the door. My notes at this point literally just say "Derek Haaaaaale!" They beat the Death Eaters out the door and onto the porch and Melissa throws down the magical security barrier.

Isaac's businessman pantomime lasts about 45 seconds. It's long enough for Allison and Chris to infiltrate Silverfinger's compound and arrive at his inner sanctum, but they are greeted by the sight of Isaac with someone else's claws to his throat, talking about, "They've got a werewolf too." The point is that Silverfinger has information and here it is:

The Death Eaters are called The Oni. They are demons. Dark, dark demons. And they're seeking out other demonic spirits. What they do is track down supernatural people and menace them until they can be sure they're not demons. Then, they tattoo their ears and bounce. Silverfinger says Chris needs to get out of their way, really, and let them find the Big Bad they're after so they can kill him. 'Cause the Big Bad, he's one of 13 kinds of kitsune. There's the Celestial Kitsune, the Wild Kitsune, the Ocean Kitsune, the Thunder Kitsune, the Lightning Kitsune, the Polar Vortex Kitsune, the Gingerbread Kitsune, the Molasses Monster Kitsune, the Queen Frostine Kitsu, the Lord Licorice Kitsune, the Mr. Mint Kitsune, the and the Nogitsune. The last one is the Big Bad, like the one that crazy hot teenage Chris saw get murdered in Japan.

Allison calls Scott to tell him to let the Death Eaters into his house. They just want to check and make sure no one inside is demon possessed. They're not going to hurt anybody. ("I'm bleeding out," Agent McCall wails in the background.) So Scott does just that. He lets them come in and sniff everybody, including Kira who is scared out of her mind that she might accidentally be evil. But she's not. They're good. Everyone is all good. The Oni do their tattoos and go, but not before Derek gives the twins a lesson in being a real pack member/best friend. He says it's not enough to kill for Scott; they have to be willing to die for him too. He also says, "She's a kitsune, idiot" re: Kira and I oh, I laughed. We haven't gotten to see enough of Derek's curmudgeon with teenagers this season.

Once the Death Eaters are gone, Melissa rushes Agent McCall to the hospital to do some operating on him and Scott says he'll go find Stiles...

...who has woken up and is just wandering around the ER all casual-like. In a supply room, he hears a whooshing noise and is stunned to find himself face-to-face with a Death Eater. Then: surrounded by Death Eaters. He tries to flee but they have him cornered. So he just takes a deep breath and closes his eyes and thrusts his hand inside one of the Death Eaters' chests and pulls out his very firefly soul.

HOLY CRAP.

HOLY CRAP.

Stiles does it to the three other Death Eaters, snatches their firefly souls and crushes them beneath the heel of his worn out Converse. When Scott finds him standing in that room all alone, he's like, "Dude, are you OK?" And Stiles just smiles sweetly at him and goes, "Yeah, man. Never better."

Next week: Young Derek Hale and Young Chris Argent face off in a shirtless battle of flashback fisticuffs. Ethan and Aidan move into Scott's bedroom and brawl about who's going to get to be Scott's big spoon and who's going to get to be Scott's little spoon. Isaac continues his slow dance out of the closet. And Stiles gets a weird feeling reading the latest issue of My Little Pony: Friendship is Magic, the one where Rarity gets kidnapped, mind controlled, possessed, and forced to become Nightmare Moon's successor.