Welcome back! Saturday is Loki's day; did you know that?

Anyway. I would like to remind everyone this an AU—alternate universe—and so some of these details and events are going to happen differently than they did in the movie. I'm using the movie as a framework.

Math pr0n lesson: The chapter title is an inverse function. By inputting a function into its inverse, it will undo what the function did. So, for example, if g is the inverse of f and I put the results f(x) into g, then I'll end up back with what I first put into f. So say x = 2 and f(x) = 6. If you put 6 into g, then you'll get 2.

We covered inverse functions awhile ago. There may be a theme involving the application of some early story titles in the series; no, you won't necessarily need to grasp the concept to enjoy the chapter, but I do want to cycle through old concepts because reasons.

Chapter 10- Loki (SHIELD(avengers))

She wants to demand, to grip hair in her fist and slam face to glass, to draw out every last drop of information until she has Clint returned to her, safe and whole.

She approaches quietly, keeps her pose hesitant and unsure, and meets shattered green eyes webbed in sick blue.

(She needs to keep calm.)

"You must be Natasha," he says, smiling crookedly, drawing closer to the edge of his cage. His eyes sparkle but there is something else, something wanting. "Barton has told me so much about you."

(She slips into old habits, harnesses rage into ice. Focus.)

XXXXXX

Tony flashes Bruce a smile.

"Loki, crazy guy downstairs, thinks he's a god?"

Bruce moves to where Tony is working and pushes readings out of the way. He meets brown eyes a bit too hurt and a bit too wanting for someone who fills a room with presence, glib and mocking in equal parts.

"But you know him. Or think you do."

Tony laughs.

"This is important. He took Agent Barton."

(The Other Guy growls.)

"Legolas, right, the archer." Tony snaps his fingers, moves away, space so that Bruce can't see his eyes. Bruce settles back and crosses his arms loosely.

"Clint," Bruce says and Tony's face twists into a grimace—guilt and pain and sorrow—then gone again.

XXXXXX

"Love is for children," she tells Loki and she means to finish, means to say more, but Loki wavers, his eyes roll for a moment, mouth going slack as he searches over the word (love) and for the first time in years Natasha Romanova is taken off-guard.

Actually startles when he snarls, a fist slamming into the glass, eyes all brittle rage, a little more blue melted away, a little more poison green swirling lost.

"What is he?" vicious snarl and Natasha hears what am I.

"A debt."

"Tell me."

XXXXXX

"What is she doing?" Thor demands, seeing Natasha speaking with his brother, voice too soft and quiet to be easily picked up. Loki's stance is all wrong, snake-smile gone. Natasha says something and for a moment Loki wavers, fingertips pressed against glass, before he snarls and his fist slams into the glass.

Thor goes to leave; a SHIELD agent tries to stop him.

"I'd get out of his way," Steve suggests to the agent as Thor scowls, hand edging towards his hammer. Thor gives a swift nod to Steve before hurrying out.

XXXXXX

Tony is nearly dancing about the lab, not able to stand still, and he goes near the spear, runs a scanner along it. Bruce follows him.

"He just looks like someone I used to know. It's stupid."

Liar he thinks. His instincts are screaming, and that awful hum-buzz-noise is back.

Worse, he realizes, the closer Tony is to the spear. Tony moves away and it fades a little again. Like it's straining under weight, ready to break, and Tony is outside force pressing down on it.

"Except it's more than that."

Tony offers Bruce a million-watt grin.

"Nope. You're reading too much into things."

"Except you know Thor, too, when no one else does."

Tony freezes and Bruce knows then, that he's right, that Tony knows Loki, that Tony is here for that, for him, just like Bruce is here for Clint, and he wonders what he's supposed to do with that knowledge.

Smash him first the Other Guy... suggests.

Bruce rubs his temple with one hand, high-pitched whine throbbing as Tony begins to pace.

XXXXXX

Coulson is waiting for Thor as he goes down the hallway, armed with a polite smile.

"Out of my way," Thor snaps because he does not know what Natasha is saying or doing to Loki, and he will not have Loki hurt.

Not more. Not again.

"I'm afraid I can't do that right now, Mr. Borson."

Thor pauses, mind catching the name that no one here should know. His eyes narrow and unbidden the lights around them flicker.

"Move aside," Thor repeats.

XXXXXX

He knows all this, Natasha thinks as she talks, but Loki's eyes are wide, pain and loss and some primal need moving beneath the surface. His face is blank—but that's his tell, goes more blank the more he's off-balance.

"He was sent to kill me. He made a different call," she finishes.

Loki smiles, a beautiful smile, that does nothing to change how blank the rest of his features are.

"And if I were to spare him?"

She wants.

"I won't let you out."

His smile only grows wider and she wonders what she missed, because it has to have been something, because this smile is honest, it's the way he smiled at Fury, and the blank is clearing away to something else and when did she get so out of practice, she can't, not now, not so close.

"You are," he purrs, "simply divine. I would take this world and you would trade it for one man?"

"Regimes fall every day. I tend not to weep over that, I'm Russian... or I was."

"And now?"

His voice is as honest as his smile, eyes shimmering mad-happy-wanting.

Natasha wants, too.

She takes the bait.

"You're making this complicated. It's not. I have red on my ledger. I want it gone." I want him back.

Loki's eyes flash and he surprises her again, not triumph or glee or anything to show he's got the upper hand:

envy-pain-jealousy-loss

"I won't let you touch him," he snarls, fist slamming against glass again. She takes a step back involuntarily, heart rate speeding up as it hasn't when working, not in years. "Not you, Dreykov's daughter, Bringer, not even this pathetic realm is enough for me to let him into your hands again. I will kill you in every way you fear, slowly, intimately, until there is nothing left, until he is made safe. He is mine."

She stares wide-eyed because this isn't about Barton, it's about what Barton means, and there's what she's missing.

"You're mad," she whispers.

"Oh, yes," he chuckles, smile all broken edges and poison. "And soon he will be too."

Mad. Insane. A different sort of mad. Anger. The Hulk.

Loki doesn't need her to let him out.

"Loki is planning to unleash the Hulk. Keep Banner in the lab, I'm on my way. Get Thor there, too." She pauses, voice professional through training and not because she is actually calm. He watches her, face blank once more—but it's a ploy. Has to be.

"Thank you for your cooperation."

His eyes are smiling.

XXXXXX

"See? She has done nothing to your brother," Phil points out as Natasha rounds the corner. Her eyes flick between him, Thor, and the shorted out lights over head. Phil smiles reassuringly.

Thor settles back on his heels. Risky, Phil knew, to mention 'Borson,' to give any indicator of what Baldr had told him and what he's put together. But it did what it was meant to.

"What is it?" he asks Natasha.

"Bruce. He wants to let the Hulk out. We need to go." Her eyes land on Thor again. "We'll need your help."

Thor hesitates, casts one last glance at the doorway Natasha just came through.

"You agreed," Phil reminds him. "You agreed that you would aid us if we found your brother. We've upheld our end of the deal. We aren't hurting him, only trying to get back what is ours."

"Come, Lady Natasha," Thor rumbles, not yet giving away what so far only Phil knows for sure, twisting on his heel and cloak sweeping behind him.

Natasha eyes the two of them; Phil tilts his head towards Thor's retreating form.

Once they're both gone, he waits a moment, then enters the door Natasha just left.

"Agent," Loki purrs as he steps into sight, smile mirror to one Phil was looking at only a few hours ago.

XXXXXX

"I'm not trying to attack you," Bruce says—snaps—and has to stop to take a deep breath. Tony keeps going near the spear, and his head feels like it's being split open with every throb. "We need to know what you know. It might help."

Tony doesn't flinch at least. He's too focused on himself, on whatever it is he thinks is there between him and the two brothers from another world.

"There isn't anything to know. Right. Okay, so I knew them, met them in Chicago, but that's it, this is the first time I've seen them in years," Tony says, words rushing, when suddenly Thor and Natasha burst into the room. Tony stumbles back towards the spear, Natasha is moving towards him, and the spear shrieks.

Smash break destroy destroy

Then Steve is there and everyone is arguing around and around—smash—and why won't they just be quiet and Steve is looking at him in concern and the noise—shrieking whining and sixteen sounds as one, some high-pitch future scale that shouldn't exist.

Destroy destroy destroysafetysafe destroy smash destroydisappeardestroy destroyfrozendisgustingthing destroy breakburn Raaaagnaaaaaaroooooo—

"Bruce. Put the spear down."

There's silence but for the roaring of the Other Guy and the whine of the spear. He looks down and his hands are curled around it; it fits like it's meant to be there. He takes a deep breath in; lets it out. Everyone is staring at him.

Bringer, it whisper-sigh-purrs in his grip, caress and a wide, gracious smile.

He sets it down very carefully on the stand. Some collective breath ghosts around the room. His hands are shaking.

Everything shrieks, explodes and shudders, twists and tears and he's drowning: anger hate loss rage destroy destroy smash smash break.

Roars and lunges for splash of red.