"I know that," he says, struggling to rein in his own temper. They're stuck out here in space, driving wedges between them will just make them weak. But she's right, even if he doesn't want to admit it; it is about him, and it's hard not feeling betrayed.

She keeps talking, and somehow her words shine a light through the haze. When he fought with the Allies, everyone had their own country and their own sense of pride. It's second nature to Steve, something he doesn't even think about. The word immigrant didn't cross his mind, because Natasha's roots are so much a part of who she is it's all he sees. A friend, an ally, and a Russian. But she's more, and he let himself forget that. She had a past before SHIELD, one he knows she's trying to make up for.

He bites his tongue, taking a proverbial step back. "You're right. Nat, I'm sorry. I wasn't thinking about that."

He lets out a puff of air and drags his hand through his hair, feeling the adrenaline seep from his muscles, leaving them tense and achy. His jaw is set, two angry lines between his eyebrows, but he works to keep his voice level.

"I just," he begins, finding he doesn't know how to say the words. He looks down. "I thought I was alone."