Title: I do solemnly swear
Rating: PG
Summary: In which our heroes learn the perils of lack of inter-team communication, and Loki has his day in court.

Set post-Avengers.

The moment of shocked silence was broken by five people talking all at once. All right, only four - Natasha maintained a grim silence even as Clint, Steve and Thor all broke into demands for explication at once, at various volumes - but Tony talked enough for any two of them.

"No way, just no fucking way! This is bullshit!" Tony shouted, his voice eventually coming on top of the hubbub. "This has got to be some trick - this is his angle! This is his smokescreen, see? The game is up and now he's trying to throw the blame. Plausible deniability and all that crap."

"Hell of a smokescreen, Tony, if the person you're supposed to be springing it on doesn't even know what you're trying to imply," Clint said darkly. "As someone who actually does covert ops for a living, I can promise you nobody would hang their exit plan on something that flimsy."

"So he screwed up! Missed his target! It happens to the best of us sometimes, right, and that bag-of-cats crazypants wasn't exactly at his sanest and most rational when he thought out this whole plan of his -"

"Excuse me? Weren't you the one who just spent the last week insisting that Loki is a criminal mastermind with a brilliantly convoluted scheme?" Steve demanded. "I think this is a possibility we have to consider very seriously."

"Oh hell no, no we don't, this is complete bullshit and I cannot believe that any of you are considering such a transparent confidence scheme for even a moment -"

This budding argument was interrupted by an increasingly irate god of thunder; while he might not be able to talk as fast as Tony, he more than made up for it in projection. "Will you not all cease this prattling and explain to me what you are talking about!" he roared, building up to a volume that actually made the windows rattle a bit.

"They're talking about mind control," Natasha said flatly.

"Mind control?" Thor looked completely blank, but an angry betrayal was beginning to creep about the edges.

Natasha met his eyes. "That scepter Loki was using," she said. "The labs are still running analysis six ways from Sunday, but they're pretty sure it was Chitauri tech, not Asgard's."

"I could have assured you it was nothing of Asgard," Thor said. "Its manufacture and purpose was as much a mystery to me as to you."

"Well, among other purposes, Loki was able to use it to take control of people," Natasha said. "He got to Selvig that way, and Clint - "

"Yeah, didn't you wonder why Clint was fronting one team on the Helicarrier attack, and then another team in New York?" Tony chirped. Clint gave him a dirty look, one that promised arrows in sensitive casing joints.

"I did not think to question it, at the time," Thor answered, giving Clint a sideways apologetic look. "It did not seem so strange to me, that any Midgardian would choose to turn away from a commander who proposed to bring ruin and slavery upon his own people. Indeed, it seemed more strange to me under those circumstances that anyone would not."

"Well, I'd like to say that I just came to my senses," Clint said stiffly, "but unfortunately it took a little more than that. Fortunately, Tasha here got the upper hand."

"Cranial recalibration," Natasha explained. "Hitting him really hard in the head. That was what broke the scepter's hold on him."

"Those were the words that Loki said, but -" Thor sat bolt upright, his expression and attitude radiating shock and horror. "Do you mean to suggest that Loki was being so controlled?"

"Yes," Steve said.

"No," Tony said at the same time.

"We don't know," Natasha said. "If the mind-control tech was theirs, not his... we don't know what went on between them before Loki stepped through that portal. We assumed it was voluntary cooperation on his part because we had no reason to think otherwise."

Thor got hold of himself with some difficulty, then shook his head, expression tight. "No, it - it's not possible. For all that Loki's thoughts are shrouded in mystery to me, I know his moves. I know the way he speaks, the way he fights. It was truly him, I would stake my right arm upon it! Surely you do not mean to imply that some other force could have been pulling my brother's strings like a puppet-master, moving his limbs for him and speaking from his mouth, and I would not notice that aught was amiss?"

"It's - it's not like that, though," Clint said hesitantly, his face pinched and greyish with the stress of reliving his own captivity. "I mean, it's not like - remote control, where someone else takes the wheel and pushes you into the backseat. You still remember everything, you still have all your skills and habits and everything like that.

"It's just that you stop caring about - the things you used to care about," Clint said, and gave Natasha a haunted look. "All your priorities get twisted, until the only thing in the world you care about is what your new master wants. Until all that's left in the universe is making his desires happen."

"But this cannot be true," Thor said, his expression suffused with hurt disbelief. "Long have I been confounded, wondering how Loki could have come to such a pass where he would commit deeds so uncharacteristic for him. Straightforward military assaults are not... are not his way, he much prefers to draw his enemy out of position with guile and so gain his objectives. Even when he was King in Asgard and the rightful commander of all our army, he chose other paths to victory than to command an assault.

"And he has never before sought power for its own sake, nor taken delight in the suffering of others. I swear to you, my friends, that he was not always thus," Thor pleaded, looking between each of his teammates earnestly. "I could not fathom what had changed and twisted him so in such a brief time. All that was left for me to think was that I had never truly understood him, that all our long years together were naught but a charade. Now you propose a means by which his very will could have been violated and taken from him, and yet no one told me that our enemy had such a power?"

"Come on, it's not like we were trying to keep this a secret!" Tony said, exasperated. "It was all in the files. I don't expect everyone to brush up on gamma radiation theory in the course of a single night, but you could at least get in the background info dump before you start playing with the big guys!"

"But Thor joined the team after the rest of us," Steve said uncertainly, glancing from Natasha to Thor. "After Stuttgart. Did he even get a file folder?"

"That would have been SHIELD's responsibility, not mine," Tony shot back, bouncing the responsibility firmly off his chest. "I was in the lab with Banner, busy trying to track down that little piece of reality-breaking tech they lost."

"Don't look at me," Clint said, raising his hands. "I was batting for the other team at the time, remember?"

Thor's expression was growing steadily darker, stormclouds coming in to block the sun. "Your one-eyed commander did describe to me the strategy for battle," he said, "but no mention was made to me of this mind-control method, nor any suggestion that Loki's will was not his own."

Several pairs of eyes shifted to Natasha, whose expression was wooden. "There wasn't time to do a full background debrief," she said. "We just hit the highlights. Since Thor knew on his arrival where to find Loki and what he'd been doing, it was assumed that Asgard had its own intelligence sources to draw on."

"We did not," Thor began heatedly, but Tony interrupted him.

"I'm not buying this," Tony objected. "Look, if he was really being mind-controlled, Loki had plenty of opportunities to break out of it. I gave him more than one tap on the head when we were fighting in Germany, and I know you did too, Cap."

"Yeah, but it takes more than just a 'tap,' doesn't it?" Steve replied. "I mean, sure, I gave him the old one-two, but he got right back up from it. From what Natasha told him about Clint, she had to completely knock him unconscious in order for it to take."

"And Loki's head was a lot tougher than mine," Clint said, and smiled grimly at the memory of a certain explosive-headed arrow. "The only one of us who was able to really hit him hard enough to slow him down was..."

"The Hulk," Steve finished for him. "I saw the crater that he left in the floor when Bruce was done with him. I'm not going to lie, I was surprised he even survived that, let alone was able to walk away after -"

"After which he became suspiciously cooperative," Tony said in a tone of disbelief. He crossed one arm over his chest, bringing the other to cover his mouth. "Shit. Shit."

Natasha raised her hands wearily. "Look, this is all an interesting debate, but kind of pointless," she said. "I got a very good close-up look of Loki when he was in that cell. Doctor Selvig, Hawkeye, all of the mind-control victims had the same tell - their eyes showed bright blue. Loki's didn't. They stayed plain green the whole time we were talking. He wasn't being mind-controlled, at least not by any kind of magic."

Tony and Clint brightened with relief; Steve frowned, sinking back into the couch. For a moment it seemed that might be the end of it, until Thor shifted uncomfortably in his seat and admitted, "But Loki's eyes are not green."

Everyone turned to stare at him. With an unhappy expression and uncomfortable demeanor, Thor went on to explain. "The All-father revealed much to me, after Loki's madness and fall, that I had not previously known," he said. "Loki is... a Jotun, what you might call a Frost Giant, and they are... very different in appearance from us. His true eyes are of a red color, common to his race. It is only by means of a sorcerous glamor that they appear as they do."

"So you're saying that this glamour could have been hiding the color change, too?" Steve said.

Thor shrugged helplessly. "I do not know, my friends. Truly I do not. The ways of illusion and sorcery are my brother's province, not my own. All I know is that if there was any aspect of himself that Loki wished to hide, then hide he would, and it is unlikely he would allow any of his foes a glimpse of the truth."

"Waitadamnminutehere," Tony sputtered, wheeling around and pointing an incredulous finger at Thor. "Loki's a frost giant? As in, blue and icy and ten feet tall? I'd think that was something we would have noticed!"

"He is small for the Jotun, yes," Thor said impatiently, "and the exact manner of this concealment he wears I do not know, except that it was maintained unconsciously for all the years of his life. Do you doubt the Allfather's word on this?"

"No," Tony said, "but I'm doubting whatever the hell you were thinking that you didn't at any point tell us any of this! Given that we were hip-deep in his schemes of world conquest, don't you think we might at some point need to know just what he was capable of? Kind of a piece of vital tactical knowledge you were holding onto there."

"I did not keep it secret," Thor retorted, beginning to get angry. "I told you - I told her - that he was not my brother by blood - "

"Yeah, you mentioned the adoption thing," Tony cut across him. "But there's a big difference between 'not biologically related' and 'actually a blue alien who can star in his own winter olympics'!"

Thor was on his feet in an instant. "By your reckoning, I am no less of an alien!" he exclaimed angrily. "What mattered the specifics of Loki's bloodlines? It was enough to know what he had already done, what he still went on to do! What need to further cement his humiliation?"

"Look, everyone just calm down!" Steve interjected himself physically into the argument before it could escalate, getting between Thor and Tony and pushing them apart. He was getting unpleasant flashbacks to the three of them fighting in the woods in a thunderstorm, while Loki sat on a cliff above them and watched. "There's no point in throwing around accusations at this late date about who should have done what and when. I think we can all agree that this failure to communicate important information is what got us into this mess in the first place."

"And in the end, it doesn't really matter, does it?" Clint said, his tone oddly resigned. Everyone's eyes went to him, and he shrugged. "I mean, we can argue all day about who should have been told what when, but the fact is that this is all speculation. It's not like we have a blood test we can run for mind control. In the end, all we've really got is Loki's word."

"What of you, Barton?" Thor demanded in a tight voice. "It was only your word, was it not, that you would not willingly choose to serve my brother's schemes?"

Clint's mouth pressed in a flat line, but he squared his shoulders and looked back at Thor head-on. "Fortunately I had a little more than that going for me," he said. "Fury witnessed Loki's little trick with the scepter himself. Even if he hadn't, I had a record at SHIELD and people who could vouch for me." His hand slid up along the back of the couch, reaching without looking, and Natasha quietly reached down and took his hand in hers. "Loki's got none of that."

"Unless your people in Asgard had some way of seeing what happened with Loki before he appeared on Earth?" Steve asked.

Reluctantly, Thor shook his head. "Heimdall's sight does not extend outside of the Nine Realms," he muttered. "Neither Loki nor any of the Chitauri became visible to us until his return by route of the Tesseract. Whatever may have passed between them in their own strange realm, we had no witness of it."

"Which means it's right back to Loki's unsupported word," Steve said. "And I'm sorry, Thor, but he just doesn't really have that much credibility right now."

"Yeah, no kidding, with the God of Lies thing and all," Tony added. "Speaking for myself, I just can't think of anything off the top of my head that could convince me this is anything other than a last-minute saving throw to get out of jail free on his part."

Silence hovered in the living room for a moment, and then Thor pushed himself slowly to his feet. His expression was dark and resolute. "I can," he said. "My friends, I beg your pardon for cutting short our time together, but I must return to Asgard ere Loki's questioning is complete."

"Uh," Tony said, unnerved by Thor's sudden atmosphere of determination. "You know I was kidding about those epic thumbscrews, right?"

Thor gave him a small, distracted smile, made a few more absent pleasantries to each of them, and bowed himself out. He eschewed the stairs entirely this time, instead stepping onto the balcony outside the plate glass window, and taking off from there with a roaring crack of thunder.

The four remaining Avengers sat listening to the last echoes of thunder fade. "Well," Tony said with feeling, "that sure sucked."

Overall, Steve could only agree. Clint gave a faint groan. "Anyone wanna bet on the odds of us hearing what went down before another month or two is out, at least?"

Nobody took that bet.

~to be continued...

Author's Notes: So, uh, yeah, I was noticing a definite lack of inter-team communication going on in Avengers. Unless Fury pulled Thor aside for a quiet debriefing, Thor never got an explanation as to why Hawkeye was fighting against them in one scene and by their side in another. And Thor never bothered to explain to the team that Loki was a frost giant, which turned out not to be an issue in the final battle but easily COULD HAVE BEEN.

Having seen the Avengers movie several times now, I am still extremely at a loss as to what was going on with Loki's eye color. The character's eyes are MEANT to be green, but in several scenes appear distinctly blue. Nevertheless in this fic I'm giving the benefit of the doubt that they did not INTEND to introduce this uncertainty, and that they were just really lazy about going and changing the actor's eye color in post-production. Harry Potter-style.