"Steve."

"Steve, no."

"Stop it, Steve."

"STEVE."

A head of perfectly sculpted blonde hair pops up from where Steve had disappeared behind one of Tony's workbenches. "What?"

"Stop babying my robots. You'll spoil them," Tony rolls his eyes as he swings his stool back around, refocusing on the holographic blueprints that hover around him. He swivels away from Steve and leans back to call across the shop. "You, bring me that set of plans – "

Tony's eyes widen with surprise as he takes in the sight of Dummy and You, both parked obediently in front of Steve as he rises, tossing a small ball from hand to hand. Two robot arms track his movements carefully, low-pitched whirs filling the space left by Tony's sudden silence. He brings a hand up to his face, scrubbing it over his eyes before opening them again. Nope. Still happening.

Tony becomes aware of his jaw hanging heavily from his face in something like awe, and actually has to bring a hand up to manually snap it shut.

Steve – his Steve – the one that feeds the stray cats outside Stark Tower, the one that always stops during his morning jogs in Central Park to pat the head of every dog he passes – Steve was playing fetch. With Tony's robots.

Jesus. Tony is so not caffeinated enough for this. Throw in a few woodland creatures, maybe a singing mouse or two, and Steve was like a goddamned Disney princess.

"Steve," Tony grinds out, fighting the chuckle working its way up from behind the reactor, "What are you doing?"

Steve turns to meet Tony's eyes, the pink of a blush threatening to work its way past the collar of his shirt.

"Welllll – " and really, Tony shouldn't like it this much when Steve is flustered, he really needs to work on that, you know, never – "I came across one of Pepper's magazines, and I was reading this article, and it said that one of the best ways to strengthen your relationship is to get to know your boyfriend's family." Steve lets all of this out in one exhaled breath, as if it takes physical effort for him to push the words out past his embarrassment. "And I figured Dummy and You were the closest you had to children…" Steve's voice trails off, his face rapidly giving ground to the blush that has long since crossed the border of his collar.

Tony's jaw threatens to make another attempt to hit the floor, and Steve shifts his weight from foot to foot as his words hang in the air between them. The ball hangs forgotten in Steve's clenched fist, while Dummy and You stay where they are, clicking and whirring intelligently as they take in the scene.

It's funny, when you think about it, this Thing that they've built between them. Because really, Tony is the kind of man who had to build himself things to talk to, the kind of man who could lock himself up for days spilling his secrets and ideas to an empty room that talked back, totally content to accept blankets and cups of coffee from outstretched arms that ended in claws instead of fingers. Family was as good a word as any, you could say.

"Family?" Tony repeats, mouth suddenly dry, and Steve's face falls.

But Steve – good, solid, amazing Steve – he takes that in stride. Not a lot of people are willing to join Tony Stark on his Island of Misfit and Mechanized Toys, but Steve is one of them, and that, well, that is one reason why Tony knows this Thing that they've built is going to last.

Tony reaches out, hooks an oil-stained finger under Steve's chin, and tilts his head up, blue eyes meeting brown for a long moment. "Family," he says again, and this time, the world is a statement. It settles in Tony's chest like a warm weight, and wraps between them, snug around them like armor. Like something familiar and warm - hands reaching out to catch, arms stretching out to hold.

Like a promise.