"I need you to help me," says Steve. "Please."

Tony looks at him. He's nervously looking down at the floor – and it's definitely out of nerves, because the carpet is not as interesting as Steve is currently making it out to be – and rocking on his heels, and seeing Captain America look so inherently worried is a sight that could make even Nick Fury acquiesce.

Tony sets down the soldering iron.

"How?" he asks.

Steve bites his lip, but doesn't show any sign of actually answering Tony's question. Tony sighs.

"I need something to go on, Cap," he says. "Otherwise I'll just invent you a talking microwave. That's not a bad idea, actually. The perfect baked potato..."

"I need to know how to tell if someone... likes you," Steve answers, finally.

Tony's blood runs cold. Steve knows. Steve has become aware of his massive and inappropriate crush on him and he's calling his bluff. Oh God. This is the end. He's going to have to pack up shop and move to somewhere where no-one knows his name, which leaves about four places on Earth as real candidates, and he won't have access to proper dentistry and all his teeth will fall out and he'll gamble away his fortune to try and numb the pain of being toothless and end up living under a bridge, where not even the trolls will take pity on him.

He clears his throat. He can do this. He can divert Steve's attention.

"Why? Do you have the hots for someone?"

Steve flushes red, and that's not what Tony was expecting. He feels his heart sink. At least Steve doesn't know, though. That's something.

Swallowing down the bitter taste of disappointment, Tony claps his hands together and tries his very best to be excited at the prospect of inventing something that could revolutionise the world as he knows it.

"I can help you, Cap," he says. "But it'll have to be through the medium of technology, because I'm not exactly great at the whole dating thing. I always just assume everyone likes me. I mean, it's always true, obviously, but they don't always want to admit it, so that can be horribly awkward."

"I don't - "

"Like me, yes, I know," Tony interrupts, because he doesn't want to hear it come from the other man's lips. It's hard enough hearing it from his own. "But regardless of my incredibly successful dating history, I can help you. Just give me a few days, OK?"

Steve opens his mouth as if to say something, then shuts it again and nods.

"OK."

Tony offers him a smile that's second place, if not winning.

"I'll let you know when it's done," he informs him, because this is essentially a business transaction, and Steve nods again.

"Thanks," he says.

"Don't mention it," says Tony. He really hopes he doesn't. His heart's already full of shrapnel. It doesn't need to be full of pointless hope as well.

Pepper comes to see him that night. He's sitting on the floor of the third largest bathroom, blueprints surrounding him, brainstorming ideas.

Pepper takes one look at him, and sighs.

"Please tell me that's not for Steve again," she says, folding her arms and leaning against the doorway. Tony looks up at her, a pen between his teeth.

"No," he lies. Pepper raises an eyebrow.

"I wasn't born yesterday, Tony."

He takes the pen from his mouth and tucks it behind his ear, turning on the charm.

"Really? But you look so youthful, Pep! Really, not a wrinkle in sight. And have you lost weight? Not that you needed to, I mean, but - "

"You have to stop doing this to yourself." She uncrosses her arms and crouches down next to him, and he can smell her perfume, the one he bought her for their second anniversary. That was the year she left him. He's surprised she kept it.

He swallows.

"Doing what? I'm not doing anything to myself," he says, the untruths coming easily with practice. "Unless you mean that, and really Pep, I keep telling you that it's a perfectly healthy habit..."

"You know, I told him to talk to you," she interjects, cutting him off mid-bullshit. "Whatever he asked you, whatever made you do this, you've misinterpreted it. He doesn't want a machine, Tony. He wants something else."

"Like what?" Tony asks, bitterly. He's sort of fed up of being told what other people want, like he has some sort of obligation to drop everything and give it to them because he's the one with the eleven figure bank account. "This is all I can give, Pep. Money and machines. And it's all I'm offering."

Pepper shakes her head, a sad expression on her face that would once have made Tony try anything to make her smile again. Now, it just makes him tired.

"You can give so much more than that, and you know it." She pulls one of the blueprints aside and inspects it half-heartedly. "I've seen it."

Tony barks out a laugh.

"And you stopped wanting it, didn't you?" he says. "And that's just it. People want this. Anything else I might want to give isn't really in particularly high demand right now. The technology stocks are looking pretty good, Pep. Everything else? Not so much."

Pepper just looks at him. She's never been easy to read, which Tony thinks has always been part of her appeal, but now it's obvious that she's disappointed.

"I want to help you, Tony," she sighs. "But I don't think you want to help yourself."

Tony's done with this. He has a machine to finish and he hasn't factored time into his day for psychoanalysis.

"Goodnight, Pepper," he says, hoping there's an air of finality to his voice.

There is. Pepper gives him one last, desperate look, and leaves.

It hurts a little that it's so easy for her to do. It's never been that simple before. Even when she left him for good, she lingered for months. The smell of her shampoo on the pillow, the jars of expensive coffee she favoured in the cupboards and the way she made Tony feel when she smiled; it's taken years for them to fade. Now, it just takes the closing of a door and she's gone.

Tony glances over one of the blueprints before giving up, his head in his hands. He's never been good with defeat, and this feels a lot like surrender.

Bruce and Thor corner him at 5pm the next day. Tony's still in bed when he hears a loud knock at his bedroom door that can only have been made by a strong, Asgardian hand.

"I'm dead," he calls out. "The funeral's tomorrow. Wear black and bring your fondest memories."

"Let us in, Stark," comes Bruce's voice from the other side. Tony curls himself more tightly into a ball of sheets in response.

"Friend Tony," cries Thor, knocking again and making the room shake. "It is most important that we speak to you now!"

"No wisdom can be gained from the tongues of the dead!" Tony shouts in reply.

"Please, Tony," calls Bruce, and he sounds a little desperate. Tony's intrigue is peaked. He can't help it. He's never been able to resist a good disaster, except for when it concerns his own life choices.

"We shall have no choice but to knock the door down!" Thor shouts.

Tony would like to see him try. He'd also like to see them leave.

"The dead tell tall tales!" he retorts.

There's a pause, and he can hear mumbled voices from outside. Then, there's the click of a lock, and the door swings open. Bruce, Thor and Natasha walk in.

"Judas," says Tony to Natasha. She shrugs.

"She used a teaspoon," states Bruce, incredulously. To prove it, Natasha waves the implement in the air.

Thor claps his hands together.

"Friend Bruce, you must fetch friend Clint at once," he orders. Surprisingly, Bruce nods curtly and leaves to do the Asgardian's bidding. "I will carry Tony over my shoulder to ensure he does not attempt to flee."

"You will not!" Tony argues.

Natasha raises an eyebrow, and Tony shrinks back into the pillows.

Thor does.

"So, just to check," Tony says. "This is a hostage situation, right?"

Clint fixes him with an irritated glare. Tony sticks his tongue out in response, and Clint looks mildly disgusted.

"You're not a hostage, Stark," Natasha informs him. "You're a friend in need," she adds, falsely sweet.

"Just so you know, I'm telling Coulson about this," Tony tells them. He shifts on the sofa slightly, trying to get more comfortable, which is a difficult task considering he's wrapped tightly in about six blankets, held together by the heavy weight of Mjolnir. "He'll serve you all a steaming hot cup of whoop-ass."

"We just want to help you," Bruce cuts in. "Because - "

"Because watching you mope over Steve whilst steadfastly refusing to do anything about it is seriously cramping our style," interrupts Clint. He pauses for effect. "Seriously. I haven't got laid in about six months, and I'm a red-blooded male, Stark. Blue balls don't become me."

"I am ashamed to be part of your boyband," Tony tells him.

"Bite me."

"No thanks, some STDs can be transferred via saliva."

Natasha stands up. Tony and Clint fall silent, wide-eyed. Tony doesn't want to end his life this way.

"Tony and Clint, be quiet. I have a teaspoon and I'm not afraid to use it," she says. She turns to Bruce. "Bruce, tell him what you know."

Bruce sighs and folds his arms.

"It's not a lot," he begins. "But you know how you're making this machine for Steve because he said he liked someone?"

"Yes," Tony replies, cautiously. He's not sure where this is going, but it can't be anywhere pretty.

"Well, you're making it because he asked you for advice, right?"

"I am."

"And there it is!" Bruce finishes, beaming triumphantly like he's just won the gold medal for thinking, rather than the bronze medal for idiocy that Tony's considering presenting to him.

"Take me back a few steps," Tony says. "Maybe to the bit where it stopped making sense, which I think was the beginning."

Bruce groans. Thor steps in.

"What friend Bruce is trying to say," he says. "Is that there are a number of people under this roof. Friend Steve could have asked any one of us for advice. Many of us have been courting the same woman for several years. However, he asked you. Surely this says something?"

Tony blinks.

"Yeah," he agrees. "It says that he didn't want to ask an alien, an assassin or a giant green goblin for help. Jesus, compared to you lot, I'm Dr Phil."

"I do not - "

"Look," Tony sighs. "I see what you're getting at. Really, I do. But it's bullshit. It is. So can you let me get back to my workshop, please? I have a life to lead."

Thor looks at Bruce. Bruce looks at Natasha. She looks at Tony, and sighs.

"Let him go," she orders. Thor lifts Mjolnir and Tony stands up, turning to face them all.

"Thanks for the intervention, guys," he says. "But please don't kidnap me again. It was very emasculating."

He thinks he hears Clint call him something incredibly rude under his breath as he leaves, but he doesn't really care. They're all clearly sipping from the crazy side of the cup.

Steve asked him because they're friends, closer friends than any of the other Avengers seem to be, with the possible exception of Natasha and Clint, who don't really count because they have history (in Budapest, of all places). He doesn't understand why they're feeding him false hope on a drip. If he wants some fake courage, he'll go to the wine cellar.

He goes to the wine cellar.

It's two days later when Tony finally feels happy enough with his invention to show Steve. It's not perfect, of course. Nothing he does seems to be these days. There's always something missing, which he thinks is sod's law. It's close enough, though. It works. That's the main thing.

Steve takes the little silver device from Tony and looks at it, a little perplexed.

"What does it do?" he asks. Tony likes this part.

"Well, contrary to its appearance, it doesn't control the television," he starts. Steve grins. Tony's getting better at making technological references that Steve will actually understand, and Steve clearly appreciates it, which doesn't help Tony's overall situation. "Basically, it's a sort of human scanner. It measures people's biological and chemical reactions to you. Point it at the person you like, and it'll scan their heart-rate, temperature, pupil dilation and a whole array of other fun and disgusting bodily parts and tell you a percentage likelihood that they feel the same way."

Steve nods, slowly.

"I think I understand," he says. "It sounds complicated."

Tony shrugs, falsely modest.

"I've made more complex sandwich toasters," he replies. Steve rolls his eyes, grinning.

"Well, it's still great," he says. He pauses. "Although, isn't it a little underhand?"

Tony frowns.

"What do you mean?"

"Well," Steve begins. "It smacks a little of privacy invasion."

Tony scoffs. This is the 21st century. Privacy is a foreign concept.

"That's not important," he says. "Trust me."

Steve shrugs.

"I'm a man from the past," he says, a little sadly. "I'll trust you on that."

"You should. I'm inherently trustworthy."

Steve laughs. He looks at the scanner again, turns it over in his hand and really looks at it in a way that people who are used to technology never really do. It makes Tony feel warm inside, like a man made of toast instead of beauty and chiselled cheekbones. It's nice to have his technology appreciated like the artwork it really is. Tony wants to thank Steve for liking everything he does, because no-one else seems to any more unless it's capable of blowing up entire continents.

Then, Steve presses the red button.

Time moves in slow motion.

The LED at the end of the scanner lights up green, and Steve looks at Tony, wide-eyed, as Tony realises with a sinking feeling that the scanner is pointed at him, and is currently measuring his biological reactions to Steve, the man he lo – really likes, and who definitely doesn't like him back because he's Steve Rogers, he's Captain America.

Tony's mind rushes from A to B to Z but he can't get out of this one. The scanner has collected all the information it needs. It's noticed his racing pulse, his slightly elevated temperature, his wide pupils, the direction of his bloodflow.

The scanner starts flashing red. Tony wants to grab it and smash it into a million pieces, because Steve knows. It's the one secret Tony's been happy to keep, and it's out.

Steve's eyes widen even more in shock. Tony gulps.

"Um," he says, eloquently and articulately.

"OK," says Steve. "Well, I - "

"Yeah," Tony agrees. "OK. I'll see you around."

And then Tony's gone, he's running down the hallway into his workshop with the newly reinforced deadlocks, and Steve's calling after him but there's no way Tony's going to turn around to hear the rejection he knows is coming. He doesn't need to hear Steve say it when he's imagined it so many times before.

He slams the doors behind him and tells JARVIS to let no-one in, on any account. He manually resets the overrides so that even Pepper will be stuck outside.

He's completely, totally and utterly screwed.

The realisation hits him hard, makes him double over and almost retch because this is the first time he's felt since Pepper, and he doesn't want a repeat of that.

He can hear Steve knocking on the door, fruitlessly telling JARVIS to let him in.

JARVIS ignores him, and so does Tony.

And of course, Steve leaves eventually. It takes two hours, but he leaves. They always do.