It happens in the middle of the night. They come to him in the garage, while he's working away at a new actuator for Dummy. Even after so long, he can remember the plans for it perfectly.
Jarvis- the human Jarvis, not the one he constructed later from memories and wishful thinking- breaks the news to him. And Tony doesn't know how to react. For the longest time he stares, dry-eyed, and thinks, with a kind of numb, awful regret, about all the work he's going to have to do now.
Tony sits the whole rest of the night, turning the bolt he was about to put in place over and over in his hands, so many thoughts in his head that they crowd each other out until it's just a chorus of voices, too loud and too fast to be heard.
At some point, he starts building again, but Tony can't really remember what he made, and it disappears over the next few days under the clutter of the workshop.
In the morning, Stane arrives. He's driven through the night to be there.
They hug, awkwardly, neither of them used to it but aware that this is a thing that should happen, and Tony buries his face- still dry- in the older man's shoulder.
"I don't know what I'm supposed to do."
It's not the first or last time in his life Tony feels ignorant, but it's the only time he confesses it. He feels dizzy, and nothing in his later life- not flying, not fighting, not throwing himself into danger time and again- will ever feel so sickening.
"You'll work it out, Tony." Stane hides the doubt in his voice well. "You're Howard's son, after all."
And it begins there: with that sudden feeling, traitorous and sharp, that Tony's not sure he wants to be Howard's son any more.