It was two hours into Arthur's hike when he slipped on a loose rock. His body wobbled precariously, teetering on the very edge of falling. Luckily, another hiker nearby reached out and grabbed onto Arthur's arm, steadying him before he could lose his balance entirely.

"Woah! You okay?"

"Fine, thank you. It's getting more difficult as we go up, isn't it."

Arthur righted himself and looked up at the other hiker, but it was too dark to make out a face – especially as the other man was covered in a neck-warmer and cowboy hat. It may have been a hot, humid summer night on the ground, but high up on Mount Fuji it felt like December, and all the hikers were dressed in thick layers. Arthur, himself, only had a nose and pair of eyes peeking out between his scarf and woolly hat.

"The problem is it's so damn dark!" The hiker's voice was American, but Arthur wasn't too surprised: Fuji was a popular destination for adventurous tourists from all over the world. "They should really say 'bring a headlamp' on the website or something!"

"Yes, I know a few people who've come to climb Fuji over the summer, but nobody even mentioned it," Arthur agreed. "It's ruddy dangerous, if you ask me."

"I know, right? And it's gonna take forever to get to the top when we can't see where we're going. I hope there's no sudden cliffs or anything…"

"No, it'll be fine," said Arthur confidently, to ease the other's doubt. "They wouldn't build the hiking path close to any dangerous areas."

"Yeah, you're right!" Arthur was pleased to hear the smile in the other's voice, glad he could be of help. "I'm Alfred, by the way."

"Arthur. Nice to meet you."

Without even noticing, Arthur and the American had set off on their hike again side by side, continuing their journey up to the top of Mount Fuji with a newfound travelling partner for company.

After half an hour or so, chatting all the way, they reached one of the trail's resting points. Every possible seat was occupied with slouching hikers, so Arthur and Alfred were forced into a dark corner by a fence to find space to sit down – meaning Arthur still didn't have any light by which to see the face of his new friend.

They'd already established that Arthur was in Japan to teach English for a year, and that Alfred was doing a year abroad in a Japanese university. So as they sat down for a much needed drink of water, the conversation turned to their recent discovery that their towns were practically right next door.

"This is so cool! I can't believe I bumped into someone who lives so close to me!" Alfred spoke up, downing almost a third of his giant bottle of water. "That means we can hang out! We could even go travelling together!"

Arthur blushed, digging his nose down into his scarf. "Don't just make plans on my behalf," Arthur grumbled.

"So…you don't wanna be friends?"

Arthur's eyes shot to Alfred in horror, cursing himself for being so cold and giving Alfred the wrong impression.

But Alfred's eyes, just visible above his neck-warmer, were crinkled in a smirk, and the hurt in his voice was clearly all an act. Arthur scowled and Alfred let out a burst of laughter before babbling on with plans for them to go to Tokyo together next weekend. It didn't need to be said out loud – they both knew they'd want to see each other again after tonight.

The two of them continued up the mountain throughout the night, stopping every now and then at the other way-stations along the trail. And all the while, they were never quite able to catch a glimpse of each other's faces. Most of the route was pitch black as the night wore on into the early hours before sunrise – and even when they did reach the rest stops, there was never space to sit near the lights and get a good look at each other.

Which was a shame, because the more time wore on, the more Arthur was sure he was falling in love. Alfred could certainly be a bit of a wanker when he wanted – he seemed to draw pleasure from teasing and getting a rise out of Arthur – but Arthur was quickly deciding that he didn't mind. Besides, Arthur could be a bastard when he wanted to, himself, so who was he to judge?

As they carried on up the mountain, Arthur learnt that despite being a wanker, Alfred was also funny, kind, modest, passionate, and intelligent. And Arthur knew, he could just tell, that there was a devastatingly handsome smile hidden under Alfred's red-white-and-blue neck-warmer. He could just hear how beautiful it was, and he was dying to see.

At dawn, Arthur and Alfred were standing on the edge of a cliff at the summit of Mount Fuji, waiting.

Finally the sun rose. A streak of orange light spread across the horizon, the sky turned blue, clouds became silver, and the world lit up. A cheer rose from the summit as the hikers could finally see the mountain they had conquered and, looking down at the world below, realised just how high they had climbed.

Arthur, meanwhile, was preoccupied waiting for his chance to see Alfred's face. He glanced sideways at his companion, and found Alfred looking right back at him.

"Oh, uh…" Alfred stammered, eyes darting away quickly. "I was just curious what you looked like. All I've been able to see all night is a nose and a pair of eyes."

Arthur smiled (though to Alfred it was just a pair of eyes crinkling). He tugged off his hat and unwound his scarf, and Alfred pulled down his neck warmer and tilted up his cowboy hat.

"I knew it," Alfred grinned, while Arthur was left speechless. "You're perfect."

A/N: Written for the 365daysofusuk drabbled calendar on tumblr. Posted on August 17th, 2014.

You'd better believe the whole time I was climbing Fuji-san I was thinking of this AU and a midnight, pitch dark, first meeting USUK fic.