A/N - Avengers Endgame broke my heart but I loved it all the same. Sam becoming the next Captain America was one of the many pleasant surprises from the movie, and I can't wait to see what they'll do with that premise in his TV show. For now though, here's a quick story dealing with the aftermath of that ending.

I hope you enjoy this and any feedback is appreciated!

Sam can't sleep.

This is hardly a new phenomenon. If anything, given recent events, it would be more surprising if he could sleep regardless of the weariness settling into his bones. Consciousness clings to him without mercy as minutes turn to hours and the moon rises ever higher, and the ceiling refuses to become more interesting no matter how much attention he grants it.

Things could be worse, he supposes. The moonlight is a pleasant alternative to the darkness that lingers beneath closed eyelids. His sparsely furnished lodgings are shrouded in a ghostly blue veil which keeps the nightmares at bay, and the bed is comfortable without being so luxurious as to drown him among soft sheets. He would expect no less from one of Banner's many safehouses; a woodland cabin in upstate New York designed to provide refuge for a few days at most. The thick layer of dust coating the surfaces upon their arrival had shown just how little need Banner had for the place once the army stopped vying for his head, but the forest had suited them well for time-travel escapades all the same.

Sam knows a lack of comfort is hardly what's keeping sleep at bay, though confronting the true cause is something he'd rather avoid. If anything, forced wakefulness is better than the alternative. If the nights following his resurrection have been any indication, his visions of Riley being shot out the sky have merely been traded in for the sensation of his own body being unmade; collapsing to dust and atoms only for him to face a ceaseless void.

He wonders if Bucky experiences the same nightmares, only to conclude that he'd rather not know.

Heaving a sigh, Sam clenches his eyes shut and deliberately counts to ten under his breath. The exhaustion lingers, as he knew it would, but he fights it anyway. He knows sleep will not come to him tonight. The ceiling swirls in a mass of grey when he reopens his eyes, but he casts aside his disorientation and forces himself to sit, discarding soft sheets as all desire to rest leaves him entirely.

The floor creaks against his weight the instant he rises, but healthy snores from the neighbouring room suggest Bruce remains undisturbed at least. Sam can hardly say the same of Steve and Bucky with any confidence. For two men perfectly capable of sleeping like the dead, in the right circumstances a pin-drop is all it takes to rouse them to action. The house remains peaceful however, no matter how loudly the floor protests to Sam's every step. The relative silence of the cabin combined with the stillness of the forest beyond should be disquieting, Sam thinks, but he pushes aside such notions as he creeps across the landing and down wooden steps, smirking at the rumbling snores emanating from Bruce's quarters.

A warm glow warns him of company before he's made it halfway down the stairs. It's no surprise when slipping into the lounge reveals Bucky resting in the same position Sam left him in hours before, legs huddled to his chest and attention fixed upon the crackling fire. Sam halts, for no reason other than to grant his friend more seconds of peace before his presence shatters it like glass.

Bucky looks older in this light. The fire dancing across unfocused eyes brings to mind the horrors lurking in his past, while the orange glow casts dark shadows across his cheeks, highlighting a weariness to mirror Sam's own. He's also in desperate need of a shave, though in this instance Sam neglects to mention it. The 'Grumpy Jesus' jokes have become so old by now that Sam himself no longer finds them funny.

Before his lurking can become creepier than it already is, Sam announces himself by clearing his throat and wanders over to the fridge to grab a beer. Newly alert eyes fix on him in a manner that remains unnerving years after that gaze last signified a desire to kill, but if there's any protest at his arrival it remains unspoken. Even the ghost of menace doesn't last. All echoes of the Winter Soldier fade in a heartbeat, to Sam's relief, though he wonders if the suspicious glee colouring Bucky's face is any better.

"Oh Captain, my Captain," Bucky salutes, lips turned up into a smirk torn halfway between conveying fondness and mockery. Neither provides Sam with any comfort, and he takes a swig of beer to drown the growing unease in his gut.

"Shut up," he utters, though there's little bite to it. Bucky obeys without hesitation – the smirk shifting to a warm smile – and if circumstances were different, Sam might have accused him of going soft. Any further retort is swallowed before he can voice it, however. He doubts either of them have the energy for a spat, no matter how playful.

As though an invisible hand has grabbed hold of his skull, Sam's attention is drawn to the shield resting where he had left it; balanced against an armchair as though it were simply another piece of furniture. Its colours shimmer and dance beneath the flickering light, rendering it almost incorporeal to the point where Sam thinks his hand might slip right through if he dares to touch it. There'd be something symbolic in that, he thinks with a frown, no matter how resolute Steve seemed when passing the torch to him.

"Did you know?" Sam asks, his voice barely above a whisper.

Bucky's brow furrows, as though Sam has presented him with an elaborate riddle rather than a simple yes or no question. For a moment the only sound is the fire crackling against blackened logs – the heat licking fiercely at Sam's skin even from a distance – and he inwardly begs for the silence to be broken before it can smother them both.

Even Sam isn't sure what exactly he's asking. Did Bucky know Steve intended to pass on the mantle of Captain America to him? Had Steve even said as much or had Bucky known out of instinct borne from years of knowing Steve better than he knew himself? Did he know that Steve would go on to experience a lifetime – or several – in the space of those five short seconds?

Hell, had Steve himself known that when the time machine took him away?

Clarification is likely unnecessary. Sam imagines the answer will be the same no matter what he asks.

In the end, all he gets is a lowered gaze and the minute nod of Bucky's head, but it's the only response he needs.

Once again, the shield calls to him like a siren. Sam sets his beer aside and lets his fingers grace the surface; the metal warmed by fire while hidden scrapes detail years of fighting. As though still expecting it to crumble in his hands, he lifts the shield with the care he would give a newborn; testing the weight and feeling his chest tighten at the knowledge that this slice of history is now his to wield.

"It feels heavier than it used to," he says, though he's not sure if he's referring to the shield itself or the responsibility he's been landed with. He wonders if this is how it felt for Steve, all those years ago. If he too felt like his body was going to collapse from the pressure resting upon his shoulders; from the burden – and privilege – that the title of Captain America carried. Or perhaps the mantle had come as easily as breathing, and the pressure Sam feels now is tied to his desire to live up to the impossible standard Steve has already set.

He eases his right arm into the leather straps, tightening them to the point of hurting. For as strong as Vibranium is, its lightness makes for a comfortable weapon. Sam brings it forth, protecting his torso from an unseen threat, and wonders how it will feel when the wings are at his back. The set-up may prove troublesome in the air. He has always valued having his hands free to aid his flight or wield a weapon or two, though he supposes with practice the new addition could work to his advantage. On the ground it will be invaluable, however; an extra source of protection at his front while the wings guard his rear.

It hits him that considering the logistics in this much depth means he's already too far gone.

"Steve wouldn't have chosen you if he didn't think you deserved it," Bucky points out.

Sam wonders how transparent his uncertainty must be for the nail to be hit on the head so precisely. In the darkness of the lounge, his fear must ripple in the air like neon while a tiny thrill of excitement struggles to overwhelm it. He looks down at the shield, unsure whether he wants to rip it off or never take it out of his sight, and wonders if he's as prepared for all that comes with it as Steve seems to think he is.

"What about you?" Sam asks, though he's not sure he wants to hear the answer. "Am I worthy in your eyes?"

It's the most sincere he's ever allowed himself to be with Bucky. Up until now Sam has tended to rely on banter, partly to avoid acknowledgement of their troubled beginnings and partly because Bucky's always ready to mock him right back.

This feels different. Hell, everything since the Battle of Wakanda has felt different, and not for the better. Both Sam and Bucky, along with trillions of creatures across the universe, were dead and gone only to wake to a world that had mourned them for five years. It's not shared life experience he would wish on anyone, but it's something he shares with Bucky that he can't quite put into words with Steve. And aside from the man himself, there's likely no-one who understands Captain America as fully as Bucky does.

Sam could always ask Steve for help in that regard. For all that their earlier conversation had carried the undercurrent of a farewell, his best friend will always be a phone-call away if Sam or any of the surviving Avengers need him. That was one thing Steve had promised; he may have lived a lifetime or two in a timeline Sam can never know, but his twilight years will be spent at home. He has grown old and lived a good life, but Sam and Bucky haven't lost him yet. Nor will they for many years, if the universe is kind.

It strikes Sam with a jolt that, before now, the concept of Steve growing old had been completely foreign to him. He'd always expected one of two things to happen; either Steve would remain ageless while Sam's own skin wrinkled and his body withered, or Sam would be fated to watch as Steve died protecting the world for the umpteenth time. Growing old and retiring seems a pipe dream in their line of work – not entirely without reason – but Steve has beaten the odds all the same.

Sam pulls himself from his thoughts before he can become lost; his exhaustion dragging him through so many tangents, he feels like a drunk trying to find his way home. The room has darkened as the fire threatens to die, though neither he nor Bucky make a move to stoke it. Bucky still appears to be considering Sam's question, his eyes distant as though he too has gotten lost within his own head.

It would hardly be the first time, Sam thinks with grim certainty.

"Steve asked me once if I was ready to follow Captain America into the jaws of death," Bucky says eventually, a private smile reaching his eyes as he's transported seventy years back in time. A nugget of memory shifts in Sam's brain, as though he's heard this story before from Steve's perspective, though any recollection is marred by the haze of alcohol. Steve's metabolism always did make him a terrible drinking partner.

"And you told him yes, I take it?" he guesses, freeing his arm from the shield and resting it gently against the armchair.

"Not quite," Bucky admits, and a soft laugh escapes him when Sam lifts a questioning eyebrow. That spark of amusement seems to de-age him by ten years, and the change is so stark Sam finds himself smiling easily as well. "Captain America was still a propaganda piece back then. If the army had its way, he'd have been performing in tights instead of saving hundreds of men."

Sam hums in understanding. He's heard this part of the story at least, between countless documentaries and Steve's own – considerably humbler – account. The tale of him rescuing the 107th from Hydra is practically legend. The fact that it had only occurred because Steve was too stubborn for his own good is partly why Sam has always liked him.

"I'd have followed Steve into Hell if he asked me to though," Bucky continues, his eyes meeting Sam's own with a stoic conviction. "I hope it never comes to that, but I think I'd be willing to do the same for you."

It takes a moment for the full implications of those words to sink in. Sam knows he must be staring dumbly, but he can't be certain that he hasn't misheard. To think that he's somehow earned the degree of trust Bucky has for his childhood friend is too absurd to consider, and yet Bucky has no reason to lie to him now. Perhaps fighting to save the universe from a genocidal maniac – twice – has granted them a certain kinship that Bucky's acknowledged with far more ease than Sam has.

The more disturbing implication is the idea that Bucky thinks Sam would ask anything of him. After everything he's been through – all those years of torture and manipulation and death – it's amazing that Bucky's managed to build some semblance of a normal life. He has a home in Wakanda, should he wish to return there, or the chance to live peacefully with Steve now that he has no more reason to fight. The idea of asking him to fight by Sam's side now seems so cruel, it hadn't even crossed his mind.

"I won't ask you to come with me," Sam promises, and if the expression flashing across Bucky's face resembles disappointment, he doesn't mention it. "It wouldn't be fair. You've earned some peace."

"Maybe," Bucky shrugs, his eyes drawn once again to the fire. Sam finally comes to sit beside him and watches the last embers fight for breath among the logs. Moonlight has slowly taken over; pale blue drowning out the orange glow while keeping the threatening darkness at bay. Sam takes some comfort in the moon's presence. Rest may still lurk beyond his grasp, but so long as the moon lingers in the sky, he doesn't have to face the responsibilities that tomorrow will bring.

He turns to Bucky and wonders what he's thinking. Wonders if he believes he deserves the life waiting for him in Wakanda or whether guilt still clings to him like a disease. Wonders if the life of a simple farmer or retired soldier would even suit him or whether there's a part of him that yearns for the fight no matter how desperately he runs from it.

"I grew up with Steve Rogers," Bucky says eventually, glancing over to Sam with a smirk that conveys all the history that sentence carries with it. "I'm not sure I'm built for peace."

A laugh escapes Sam before he can stop it, causing Bucky to respond with a shit-eating grin of his own. The image of Steve being awoken by the noise only to find his two best friends laughing at his expense threatens to make the situation worse, but Sam controls himself out of courtesy for the cabin's sleeping occupants.

He supposes he can relate to Bucky's situation. After Riley's death he'd been so sure he was done. He'd gone home from his second tour with a grief-stricken sense of 'good riddance' and had enjoyed a quiet lifestyle in the aftermath; free from orders and using his skills to help veterans with experiences similar to his own.

Until Steve had overtaken him during a morning run. One chance encounter that had transformed his life over the course of a week. It's only in retrospect that Sam appreciates just how willingly he'd leapt back into the fight; how he'd risked his life without a second thought simply because Captain America needed his help. He'd never once regretted that decision. Not even a life on the run or death itself had made him regret following Steve into battle.

Sam only hopes he's worthy of asking the same of Bucky, if Bucky is willing to fight by his side.

"Besides," Bucky says, once the laughter has died down and an unspoken understanding has settled between them. "Someone needs to keep your ass out of trouble."

"Oh, so that's how it is?" Sam asks, clutching his chest in mock offence while Bucky smirks, clearly enjoying the situation.

"That's how it is," he agrees, though it isn't long before a warm smile returns to his face and the veil of sincerity washes over them again.

So that's that. As of the morn, Steve will have officially retired as Captain America and Sam will take over the mantle, bearing all the responsibility that comes with it. Bucky will be by his side, for as long as he wants to be. If there ever comes a time where he no longer wishes to fight, Sam knows he will allow it as easily as Steve would have let him go in the same circumstances. He already knows what it's like to watch one friend die by his side. If he can spare Bucky from the same fate, he'll do it in a heartbeat.

It occurs to him that he doesn't even know where they'll go. Home was the Avengers Compound once, but the building is now buried in a heap of ash and metal. Efforts are already in place to rebuild it – and the Avengers with it – but it could be a long time before they have a functioning base of operations. As much as Sam would like to believe that the absence of Thanos will grant them a moment's peace, the return of half the world's population will most certainly bring its own trials and tribulations, with assailants eager to take advantage of a planet thrown into chaos. Accepting the role of Captain America means accepting it immediately; he could have a mission under his belt before the week is done.

It's a lot to take on, but Sam thinks he's ready.

"Well then," Sam says, releasing a breath that seems to carry the weight of the world with it. His eyes are drawn to the shield one last time, though the magical qualities it seemed to possess earlier have gone. It feels real, tangible. It's his for the taking should he want it, and that's a surreal thought if ever there was one. "Are you ready to follow Captain America into the jaws of death?"

"Hell no," Bucky laughs, and a fond smile tugs at Sam's lips before he can stop it. "That guy with the wings who's a colossal pain in my ass. I'm following him."