It had been a long case. Not just normal long, but completely, ridiculously, long. And away from home too.

They'd been shacked up in some small town in Ireland (Arklow, Sherlock had told him, which meant absolutely nothing to John), and Sherlock had gotten them rooms in a quaint little B&B. Same room, but separate beds. Thank goodness.

The first night, John had fallen onto the bed, fully clothed and passed out. He wasn't sure what Sherlock did all night, but he was quiet, or at least he was quiet enough to not wake John up or irritate other guests.

They were off again at the crack of dawn, Sherlock bounding with energy and John struggling to keep up. He didn't know how the detective did it.

The second night John managed to change from his clothes before falling asleep. He was also absolutely sure that he hadn't managed to crawl under the blankets, yet when he woke up, found himself neatly tucked in. (Sherlock claimed to have no knowledge of that.)

The third day was more tame, and was spent mostly scouting out the industrial area, looking for clues.

John was able to change and get under the covers that night, leaving Sherlock perched in the chair. He mumbled something at Sherlock about needing sleep, which he ignored. John didn't have the energy to fight it, and drifted off.

The fourth day was the conclusion to the case. Sherlock had solved it, a criminal was caught, John had claimed it was 'brilliant', and all was rather well with the world.

It was too late to check out of the hotel, so they just stayed another night. John actually thought this was a good plan, because he was too tired to travel, and knowing Sherlock probably hadn't slept for the past five days, figured it would be good for him to sleep a bit.

Sure enough, as soon as they arrived back at the room, Sherlock collapsed onto the bed. John actually spent several minutes poking him, trying to get him to wake up and get changed, or at least remove his coat, but it was useless. Sherlock was dead to the world.

So John rolled Sherlock onto his side and removed his coat for him, then tucked him under the covers just as he was sure Sherlock had done for him the other night.

John examined Sherlock for several minutes, commenting to him "I don't know how you sleep when it's so light in here. You come in, turn all the lights on, open all the curtains, then fall unconscious on the bed."

John sighed and reached a hand out to ruffle Sherlock's hair. John didn't understand how it could be so ridiculously... curly. And bouncy. They were like little springs. It baffled him. And he rarely got a chance to examine it closely. And after he tried to awaken Sherlock to remove his coat, John figured that playing with his hair wasn't likely to wake him.

John pulled the chair up beside the bed and positioned the lamp in the best place so he could see Sherlock's hair clearly.

"For science," he informed Sherlock's sleeping body. And with that, he selected one of the curls on top, pulled it back, and let go. It recoiled and John giggled.

"Perhaps," he mused, "if I hold it for longer, it won't recoil as quickly."

Sleeping Sherlock seemed to agree, and John took this as permission.

He grabbed the same curl and stretched it out, holding it there while he wondered how long 'longer' was.

He'd just decided that it was about long enough when he was distracted with something on? In? Near? Sherlock's hair.

"This requires further investigation," he informed Sherlock.

John leaned in closer, examining the base of the hair, trying to figure out exactly what it was that was different.

"Oh!" he said suddenly, letting go of the curl (which, disappointingly, recoiled just as quickly as it had previously) and hopping off the chair.

He dug around in Sherlock's coat pockets until he found what he was looking for: Sherlock's magnifying glass.

Feeling rather clever, John held it up to Sherlock's hair and examined it again.

"It's almost like..." John began, pausing as he tried to figure out what word he wanted. "Like..." he frowned, "it's dyed or something. Which seems..."

John trailed off, his brain catching up with his eyes.

"Oh!" he exhaled. "Interesting."

John had a theory, but it would require Sherlock being awake to confirm (or deny) it. John gave up on the curl experiment and went to have a shower.

He managed to make it under the covers again that night.

The sun was once again shining in the curtains that he'd forgotten to close when John awoke. Sherlock was stirring as well, still in the same position John had left him the night before.

John brightened when he remembered his discovery.

He popped off to the bathroom to get dressed. Sherlock still hadn't moved by the time he got back.

John frowned.

"Sherlock," he sang, "it's time to get up!"

John felt inclined to open the curtains, except they already were.

Sherlock stirred. Barely.

John moved closer and began poking him.

"Sherlock," he said with each poke. "Sherlock, Sherlock, Sherlock, Sherlock-"

"What?" Sherlock snapped, pushing John's arm away.

"It's time to get up. AND," he continued, "I have an experiment to finish that I need your help with."

Sherlock perked up slightly at that.

"What kind of experiment?"

"Not telling," John replied smugly. "At least not until you get up."

Sherlock sighed dramatically.

"Don't give me that. It wouldn't be so bad if you had slept sometime in the last couple of days."

He rolled his eyes as Sherlock burrowed back under the covers. "No, no," he said (reminding Sherlock of a time that he had said that while he was crawling around on the floor after being drugged) yanking the blanket off the end of the bed.

Sherlock was exposed to the bright sunlight.

"God, you are ridiculously pale," John said, rolling his eyes. Somehow, without moving at all during the night, Sherlock had managed to tangle his shirt, rolling the sleeves up and exposing his stomach.

Sherlock glared at him.

"Come on," John said with a grin. "Up!"

Sherlock groaned, but managed to roll off the bed.

"Experiment, remember?"

Sherlock only glared at him again.

John smiled larger. "Just go get dressed, then we'll talk about it. And we have to figure out when we're going home today," he called after him, Sherlock slamming the door in his face.

John sat back in his chair, smiling to himself. He was rather proud of his observation.

Sherlock skulked out a few minutes later, having ignored John's requests to get dressed.

"So," he said, making an attempt at looking disinterested, and failing miserably. "What is this experiment you're talking about?"

"Well," John began, rather enjoying this power he had over Sherlock. "When you passed out on the bed last night, I was conducting an experiment with your hair."

"My hair?" Sherlock asked dubiously.

"Erm... yeah. Anyway. That experiment was sidelined when I noticed something." Sherlock smirked at this.

John rolled his eyes in response. "Get over it already. Anyway," he continued, "I noticed that the base of your hair was a different colour than the rest of it. Like you dye it," he concluded, rather pleased with himself.

Sherlock looked at him, expressionless. "So?"

John gaped. "So? I notice something and that's all you have to say?"

Sherlock sighed, speaking to John as if he was a child. "You noticed something. Great. But what does it mean?" he enunciated clearly.

John blinked. "Well... the base of the hair is really really light, and if you combine that with the colour of your eyes, skin, and your intense dislike for the sun... it all leads me to think you're albino."

Sherlock examined him for a moment before nodding slightly.

John felt a flush in his chest that may have been pride.

"So... why?"

Sherlock rolled his eyes, hands clasped beneath his chin as he leaned back against the pillows on the bed. "I assume you're asking why I dye my hair, which is an extension of the question why I didn't tell you. And the answer is to that simple. Because it wasn't important, interesting, or necessary." Sherlock looked to John, gauging his reaction.

John pondered that. "You didn't answer my actual question," he pointed out.

Sighing, Sherlock replied, "yes, well, I'd rather hoped that I wouldn't have to."

"Sherlock, as you've pointed out before, I'm your only friend. You can tell me."

Sherlock glowered at him, obviously not pleased with John pulling the 'friend' card.

"Because I look ridiculous otherwise," he finally said.

John thought about that for a minute, picturing Sherlock with the typical white, almost translucent hair of albinos. He couldn't help it. He snickered.

He was pretty sure Sherlock was going to kill him, but when he managed to glance over at Sherlock, the detective was cracking a smile.

"Yup," John managed, still giggling.

"Yup," Sherlock replied, still grinning. "And if you tell anyone else, I'll kill you."

"I assume Mycroft knows," John said, finally catching his breath.

Sherlock rolled his eyes. "Of course he knows. He knows everything. The next time you see him, he'll know that you know, and then where will we be?"

Sherlock smirked and turned to his phone.

"There's a ferry leaving at one. We'd best be on it."

John had also turned to his phone, and just as Sherlock finished that sentence, John burst out laughing, almost falling out of his chair.

"What?" Sherlock asked, not even bothering to hide his curiosity.

Still dying, John only held out his phone.

"Is this... an albino otter? Why is that so funny?"

Still gasping for breath John managed "because it looks like you."

Sure enough, the otter had his hands clasped beneath his chin, in a very similar position to Sherlock's thinking pose.

Sherlock rolled his eyes. "You need to get out more."

John fell out of his chair with a satisfying thud, and continued to giggle.

Sherlock wasn't going to admit it, but it did remind him of himself. Just a tiny bit.