Bucky gestures for Sam to go ahead and address this Old Steve, not sure how he’s feeling about it. He suspected that Steve might have stayed in the past and chosen to grow old, but he had thought… Well, he had thought that Steve would choose him, and this future they could have figured out together.
He watches as Old Steve gives Sam the shield, and he knows that Sam is going to make a great Captain America, but he can tell that Sam feels a little bit the same way he does–that Steve chose a life without them.
Suddenly, there’s a zapping sound behind them and Bucky turns to see Steve–present Steve–stumbling onto the platform with a grin. He takes one look at the bench, where Old Steve is grinning back and Sam’s mouth has dropped open, and he lets out a sharp bark of laughter.
“It worked!” he cries, and his older counterpart laughs along with him.
Bucky is confused, but even moreso when he hears another voice say, “I still can’t believe this is what America’s greatest strategic thinker uses his brains for.”
He looks behind the platform to see Bruce standing back, baffled, as an old version of… Bucky himself stands by the console and clicks a few more buttons. Old Bucky (holy shit) catches his eye and winks.
At this point, Steve (both Steves, really) have stopped laughing but they both still look like kids on Christmas morning.
“Will someone explain this to me?” Sam says, the hand not holding the shield pressed to his heart like a housewife from the sixties, looking like he’s not sure if he should be offended by what is happening. Bucky feels the same–he’s still processing the fact that it seems like Steve hadn’t chosen a life without them after all.
Steve–present Steve, his Steve–scratches the back of his neck, smile still wide. “I thought it would be funny if you guys thought I stayed behind and grew old, just for a little bit.”
It’s Bucky’s turn for his mouth to drop open. Sam’s fingers twitch in the shield’s straps like he wants to punch Steve.
“That sounds like a stupid reason to play with time travel, Steven,” Bucky says in a measured tone of voice.
“But why?” Sam’s eye is twitching a little too. Bucky’s starting to be amused by the whole thing, if only because of Sam’s expression.
Old Steve pipes up. “To see the look on your lovely face, Sam. Why else?”
Both Bucky and Old Bucky crack up at the same time, and present Steve just nods.
“What the fuck, Steve!” Sam sounds angry but the corner of Sam’s mouth is starting to quirk up.
“How did you know future you would show up?” Bucky asks, looking at Steve, stupid Steve, present Steve, young and glorious and still here to have a future with.
“Well, I didn’t really, but I figured if we figured out how to time travel now, it’d only get easier in the future, right? And you’re already here so obviously you would help me.” Steve gives him a sunshine smile, the angelic one he likes to wear when he’s being especially annoying.
“Obviously,” Bucky says back at him. He’s too busy smiling back helplessly for the sarcasm to really come through.
“Obviously,” Old Bucky repeats, amused. At some point, Old Steve circled around and found his way back to Old Bucky’s side, and he’s put his arm around Old Bucky’s waist. Bucky smiles wider, looking at what’s become clear to him is his future.
Sam shakes his head but he looks like he’s getting over it. “So is the shield yours after all then?”
“Oh, no, that’s yours. I was actually planning on telling you I want you to take over; I didn’t realize that part would be done by now too,” Steve says.
Old Steve’s eyes twinkle. “I remembered your shield was just a little broken at this point, so I thought I’d just give you that one and just tell you on his–my younger self’s?–behalf.”
“Wait wait are you starting a paradox? How does the shield ever get repaired if you’re just giving him a future shield now? How can you be in two places at once?” Bruce is looking slightly panicked, which is valid. Steve didn’t accidentally fuck up the the time-space continuum did he?
Old Steve just smiles enigmatically and waves a hand. “We figure it out, don’t worry Bruce.”
“We should go, Stevie,” Old Bucky says.
“Right.” They clasp hands and Old Bucky’s still shaking his head. Old Steve looks at Bucky and sighs dreamily. “You’ve always been a looker, Buck.”
Old Bucky seems busy ogling present Steve, who has come up to stand beside Bucky. “Speak for yourself,” he says, before looking at Bucky one more time and smiling. “He means it, kid. End of the line.”
Bucky looks up at present Steve, and Steve slips his hand into his, mirroring their older counterparts.
Old Steve looks back at Sam and raises his and Old Bucky’s clasped hands. “More details on my marriage, he says with a grin. Before Sam can reply, he says, "See you guys later,” and between one blink and the next, they’re gone. Bucky’s heart warms at the fact that, no matter what happens, he’ll end up old, married to Steve, and still pranking Sam. What a life.
There’s a pause before Sam just sighs loudly. “I can’t believe you,” he says to Steve, annoyed and fond. “I cannot believe you’re stubborn enough to hang onto the idea of a prank for fifty years just to get me to feel like an idiot.”
“Always worth it, Sam,” Steve says in his USO showgirl voice, saluting with the hand not holding Bucky’s.
“Unbelievable,” Sam mutters under his breath, but he’s just straight-up smiling now. Bucky can tell he’s happy Steve didn’t choose to live a lifee without them after all.
Sam leaves with Bruce in tow, leaving just Steve and Bucky.
Bucky whacks him upside the head, and Steve yelps before rubbing where Bucky hit.
“Okay, maybe I deserve that,” he says.
“I thought you left us, idiot,” Bucky says back, clutching Steve’s hand a little harder. “I thought you chose to be happy with Peggy–” Steve makes a noise like he wants to interrupt but Bucky continues, “which would have been fine. You deserve happiness, Steve. You deaerve rest.”
Steve pulls Bucky until they’re facing each other, and cups Bucky’s cheek. “Why do you think I gave the shield to Sam? I’m choosing rest, Buck. Choosing happiness.” Steve’s thumb goes over the ridge of Bucky’s cheek and he feels himself flush. “I’m choosing you.”
“Oh,” Bucky says, softly.
“I did get that dance with Peggy though. I owed her. But like she’s told me before–or after, I guess, for her? Anyways, she’s happy with a husband and kids of her own. My place is in the future–the present–fuck, time travel.” Steve huffs before leaning his forehead on Bucky’s. “My place is with you. It’s not the end of the line just yet, Buck, and you’re stuck with me."
Bucky smiles, thinking of Old Steve and Old Bucky, and how clearly fifty or sixty years from now, he’s still just going along with whatever plans this man and his stupid brain cook up, following along because how can he not? Bucky will never be able to stop following him. "Clearly,” is all he says, in a very dry manner, but Steve laughs loud and bright.
“Let’s figure out retirement, Buck. What d'you say?”
Bucky just laughs in response, just as bright, and kisses Steve on his stupid mouth.
“I’d say this line is looking real long, and I wouldn’t want it any other way.”