It was an early spring morning in northern Argentina, mid-November with dew on the ground and that refreshing cool spring breeze that came this time of year. Sam knew about the dew because for some reason he'd agreed with Steve to wake up at this ungodly hour and go for a run. Not that he'd be able to keep up with the man.

Thankfully Steve had stopped not far ahead in a small meadow (park? They weren't exactly in a populated area). Sam slowed his run and approached at a light jog. Except… Steve was talking to someone? At first Sam thought Steve might have his comm. in, might be receiving new intel that would send them somewhere else on what would undoubtedly become a worldwide search for the Winter Solider, but it didn't look like that was the case.

True, the earbuds SHIELD came up with these days were practically invisible, but Sam wasn't afraid to admit that he was good with people – good at reading them. And Steve was keeping his gaze relatively centered on one location, smiling, nodding, and gesturing with his hands. All things you did when speaking to someone in front of you – not someone who couldn't see you.

But there was no one in front of Steve.

Sam knew Steve had had it rough, but he was pretty sure he would have known by now if Steve was having full blown hallucinations.

"…looking for my friend Bucky," Steve was saying as Sam got closer. He paused, as if listening to a response.

"Uh… buddy?" Sam asked in the silence. "Everything alright?"

Steve spun to face him, confusion on his face. "What? Yeah, I'm just talking with…" he gestured next to him as he spoke but trailed off as he evidently realized he was pointing to empty space. "Oh. You can't…" He looked, almost… upset, for a moment, but his gaze settled on the patch of empty space he'd been conversing with earlier, as though he was listening to someone.

If this was a hallucination, it was pretty thorough. "Can't what?" Sam asked.

"I… realize this is going to sound completely insane," Steve said after a moment. "But… do you believe in Santa Claus?"

Sam blinked. "Yeah, you were right. That's… what does that have to do with anything?"

But Steve only frowned, and glanced to the side again. "No, wait," he said, clearly not talking to Sam, "just give him a moment."

"Steve?" Sam asked hesitantly, sure his concern was showing on his face.

Steve shook his head. "This would be a lot easier if Natasha was here," he mumbled under his breath.

"What would be a lot easier?" Sam asked, though he knew the statement hadn't been directed at him.

Steve squared his shoulders, straightening his stance. Sam recognized that look – Steve had decided to just get it out with, to be blunt and straightforward.

"Introducing the two of you to each other," he said simply. "Sam, this is Rapunzel Meadows, the spirit of spring. Rapunzel, this is Sam Wilson, former paratrooper. He's helping me look for Bucky."

Sam glanced between Steve and the empty space he was gesturing to. Alright, think about this logically Sam, he thought to himself. Steve had a weird life, and a lot of weird friends, and Sam really couldn't picture the man developing full blown hallucinations overnight.

He studied the empty space again. "Hello… Rapunzel?" He turned to Steve. "She's… invisible?"

Steve seemed to relax slightly, seemingly grateful to be believed. "Sort of," he said.

Alright, this Sam could deal with. Between knowing that Steve's acquaintances (friends?) included a man who could turn into a much-larger, much-angrier, green version of himself, and a man from another world who was thousands of years old (a least a thousand?) whose brother could do magic (and was also evil…), as well as the fact that Steve was practically a hundred and had been frozen in stasis for decades…

Well, Sam could do invisible. After all that, invisible was easy. Heck, the helicarriers that SHIELD had had (before they'd turned out to be Nazis and Sam had helped take them down) had been able to cloak themselves. Maybe Rapunzel was just another genius like Stark.

Either way, technology or some form of "magic powers", Sam was much more willing to go with the invisible thing than believe that Steve wasn't quite all there anymore. (He had been fine this morning, anyway.)

"She says hello too," Steve told him, grinning slightly.

Sam quirked an eyebrow, nodding in what he hoped was the direction of the invisible woman. "So, why can you see her and not me? Don't tell me it's your enhanced senses?" he asked, semi-sarcastically. (He did what Steve did, just slower. And maybe a little bit more blind, a little bit deafer. They couldn't all be enhanced.)

"That's the 'sort of' part…" Steve said sheepishly, looking unsure of how to explain himself properly. "You have to … to believe she exists in order to be able to see her."

What? But Sam did believe that Steve had an invisible friend standing there, didn't he? Unfortunately (for this moment at least), Sam had experience in working with the brain as well. If he really thought about it, then the truth was that he wanted to believe Steve, he really did. He just… needed to see things with his own eyes. Needed a bit more than the shock of walking up to find Steve talking to thin air.

But he couldn't say that to Steve, couldn't admit that he had his doubts. (If what Steve said was true though, then it must have been obvious enough that he didn't quite believe).

"Who, exactly, is she?" Sam asked, suddenly remembering a comment Steve had voiced earlier. "And what does she have to do with Santa Claus?"

"Rapunzel is the spirit of spring," Steve said, "and, like Santa Claus, she has to be believed in to be seen."

Maybe it was the sincere way Steve had spoken, maybe it was the fact that he'd always wanted to believe his friend, maybe it was because he remembered a conversation he'd overheard between Steve and Natasha that the spirit of fall had been mentioned in, maybe it was a combination of all of these things, or none of them at all. Either way, Sam processed Steve's statement, blinked, and suddenly there was a young woman with them, sitting atop a pale white horse.

He blinked again. "Oh. Hello."

In the midst of his shocked stupor, he almost missed the woman's polite response.

"Hello," she said kindly, smiling down at him and giving a small wave.

She was… not what he was expecting Steve's invisible friend to look like. On the other hand, if she truly was the spirit of spring than her appearance matched her job fairly well. She had short brown hair, bare feet, and wore a purple dress clearly designed for horseback riding.

"I…" Sam didn't quite know what to say at first, but he was rapidly adjusting to the crazy life that Steve had dragged him into. (Oh, who was he kidding? He'd leapt in head first, especially after Steve and Natasha had gotten him his wings back.) "It's a pleasure to meet you."

Rapunzel inclined her head slightly in agreement. "And you as well. Steve was just telling me all about your adventures, and your quest to find his friend."

"Quest?"

The young woman laughed, pleasant and kind. "An old-fashioned word, I guess, but then again I'm far older than I look."

"No," Sam countered, "it fits. Of course, if Steve is the knight and Bucky the mythical object, I'm not sure where that leaves me."

"The trusted companion," Rapunzel said easily, grinning.

"I thought that was me," came a voice from behind them.

Sam jumped, not having known that Natasha was coming up behind them, but he relaxed quickly, not at all surprised. He put a hand over his heard in mock shock. "If you keep scaring me like that you'll be the only companion," he joked.

Natasha grinned at him, small and sly and all too pleased with herself, then turned to greet Rapunzel.

From there Steve resumed filling in the young woman on everything that had happened to them since the last time they'd seen each other (including some things that Sam didn't know about), as well as their current goal of finding Bucky.

Rapunzel reacted sympathetically, genuinely shocked and outraged when she heard of all that had happened to Sergeant James Barnes, as well as the fact that Hydra had infiltrated SHIELD.

They settled in as they talked, getting comfortable and confident in the fact that they were in such an isolated area of the world that they didn't have to worry about getting interrupted or being overheard.

Sam was, for the most part, still silent, still processing things. An invisible spirit of spring, who had to be believed in to be seen. Santa Claus, who was apparently real. What did it say about him that he had accepted Steve's words so easily, that Rapunzel and her horse had sprung into his view after only a few passionate arguments? He pushed that line of thinking aside: he had no reason not to trust Steve, had fought by the man's side, and it was highly unlikely that Rapunzel was a mass hallucination.

As the conversation in front of him seemed to be winding down, Sam took the opportunity to jump in.

"So how did you guys meet, exactly?" he asked. "You know, if you have to believe in her to see her?" Because neither Steve nor Natasha seemed like the sort of person to genuinely believe in Santa Claus, not without proof.

"The Battle of New York, actually," Steve said, expression slightly somber as he thought back to that time.

"In the heat of battle, you see what you need to to survive," Natasha added wisely.

That was a bit more serious than whatever Sam had expected them to say, but also entirely believable. He turned to Rapunzel, and asked her questions about what being the spirit of spring entailed. If he was going to get wrapped up into Steve's crazy world, he wanted to know everything about it that he could.

They didn't stay with Rapunzel too long after that, the spirit going her own way before long, but her visit brought with her a sense of peace. Steve and Natasha were both more relaxed, calmer. After the mess with SHIELD and HYDRA, after Bucky, there was something to be said for knowing you were not alone, that you still had friends out there in the world who have your back.

Rapunzel promised to keep an eye out for anyone resembling Bucky's description, promised to tell her friends his story, and spread the word among the other immortals. She hugged all three of them before she left, and Sam would have had to have been blind to not have noticed the way both Steve and Natasha gave into the hugs, relaxing in a way he didn't know was possible for either of them.

As for Sam… he was still in shock a bit. Startled by the existence of a whole other side to the world he lived in, the world he'd finally thought held no more surprises, after he took up with two of the Avengers. He should have known better. He thought of what his friends had said: how they had first met Rapunzel during the Battle of New York, when they'd had to be ready to believe in anything and everything in order to survive.

It wasn't quite the same thing, but thinking back to how easily he had accepted Rapunzel's existence, Sam realized that was part of his decision as well.

There was no telling what they would run into during their search for Bucky, or how long it would take. If he couldn't trust Steve and Natasha, then there was no hope for their search. Aside from lifting his friends' spirits, Rapunzel's visit had shown him how much he trusted them, and gave him more confidence as well.

Maybe this quest wouldn't be so impossible after all.

AN: Well that was... a very long wait. The story's not abandoned, but updates will continue to be very sporadic. Thor: The Dark World is next, and I haven't forgotten the possibility of introducing the Avengers to the Guardians.

Thanks for everyone who's favorited, followed, or reviewed - you're the reason this story keeps coming.

Hope you like this chapter, let me know what you think!