After picking up his and Sherlock's favorite cereal from the store, John headed home. As usual. And as usual, Sherlock was up to some sort of experiment. Except this one was different. Much different than usual.

This one was pleasant.

When John opened the door to their flat, he was immediately greeted by the beauty of the night sky. Except it wasn't the real night sky, but instead, hundreds, perhaps thousands, of glow-in-the-dark stars. Some of them were as big as his palm, others as tiny as his fingerprints. And they were everywhere–they covered the floors as well as the ceiling and walls, and he even saw some on the surfaces of the furniture.

Have we been invaded by martians or something?

"Sherlock?" John called out into the galaxy that had blown through their flat. He went over to the kitchen and left their cereal on the counter. "Sherlock!" He called a bit louder this time.

"What is it, John? I'm right here." John nearly jumped out of his skin, realizing that Sherlock had been sitting in his chair the whole time. "Your voice indicates that you're distressed."

"This." John gestured wildly around the room. "What's with the stars, Sherlock?"

"Lestrade."

"Lestrade gave you glowing stars?"

"No, of course not. It's just a case."

"With…stars." John said slowly.

Sherlock gave an exasperated sigh. "Why are you so transfixed by the stars? I assume that I have not misplaced a constellation or anything, have I?"

"I thought you didn't care about that stuff."

"On the contrary, I believe stars movements are important for navigation. Which has the potential to be very helpful when being a consultant for the police. But I am actually testing how long these stars can hold light after being under certain conditions. Sunlight, artificial light, indirect light from a window, the position of the stars in the room, et cetera."

"Oh. Wow. I'm…well, I'm impressed." He walked over to the window, his back facing Sherlock.

"Why? Usually you are disgusted with my experiments."

"This isn't like finding a severed head in the fridge, Sherlock. This is…beautiful. I had these things as a kid. I used to be afraid of the dark, and my parents put up these things to help me fall asleep. They told me that the stars would guide me through my room if I ever needed to get out." He picked up one of the stars resting on the couch and ran his thumb across it.

"Why would you need to get out?"

"I dunno. I was just a dumb kid. I was scared of ridiculous things, like most people. You can't tell me you weren't afraid of something stupid."

"Thunderstorms."

"Really? Wow. I didn't picture you as the type."

"I'd really rather not talk about it." Sherlock picked up his violin and began to play, it sounded like Debussy, but John wasn't exactly an expert. But he was always enchanted by Sherlock's violin. He found it shocking that this man could be so wonderful in such unconventional ways, in ways that people couldn't be bothered to look for. It wasn't until the song was over that John realized he had been staring.

"So you like them?" Sherlock asked quietly.

John gave a very soft smile. "Yes, I do actually. It makes me feel like I'm walking through some of the best parts of my childhood. This is stupid, but I kept those stars on my ceiling until I was 17. I used to look up at them and think how sad it was that I might be the only person with something so beautiful in my room. That was just for me." He gave a tense cough, realizing that he was becoming too sentimental. He wasn't ready to open up yet. Not to Sherlock.

"Are you still afraid of the dark?"

"Not really anymore. But I think everybody is. I think it's one of those things that binds humanity together."

"That's very insightful, John. And a fascinating idea."

Not knowing whether or not to take the latter as a compliment or not, John found that he was not hungry, but exhausted. "Well, I think I'm going to go to bed."

Sherlock nodded. "Good night, John. Sleep well." With his back to him as he walked away, he didn't see it, but Sherlock was staring at him with a small, and yet very distinct, smile.

And then he got an idea.

"John?" He called.

He appeared a few moments later. Loyal as ever. "Yes?"

"I was thinking–"

"Oh no…" John gave a huge sigh, actually looking worried.

"I thought I would sleep out here, under the stars. Would you care to join me?" Sherlock continued, as though he hadn't heard John's comment.

"Oh. That would be lovely actually. I would like that very much."

Sherlock gave him the sly, one sided smile that he knew made John's breath shaky.

"I would too."