Dust
John screamed as his best friend fell through the air.
The man who had saved him from the abyss had been taken by it himself.
Sunlight dawned on 221B Baker Street. Dust floated in a ray of sunlight through the boards that covered the windows. Sherlock's skull sat on a cold window ledge slowly crumbling away, like the rest of the skeleton which was buried under the Pleasance Courtyard in Edinburgh - or so Sherlock had once told John. Most of what Sherlock told John was unbelievable, but John knew that he must believe. After all, he was the only one that still did.
John hadn't visited Baker Street for almost three years. He still paid the rent, thinking that the day he gave up the flat, the dream would really be over. Sherlock would be gone forever and John would fall back into a black hole of depression, woken every night by his screaming comrades, missing arms, legs, souls.
As he stepped gingerly over the floorboards - taking care not to disturb Sherlock's notes and long-forgotten experiments – he noticed something. In the corner of his eye, on the violin case, there was a long finger mark. Cautiously, the blonde-haired man walked towards it. He hardly dared breathe, in case he blew away the dust and it was nothing, just a trick of the light. Suddenly, a pigeon took flight outside the window, causing John to leap backwards in fright, hitting the chair and knocking over something slimy in a glass jar.
"Oh for God's sake John, that was the last known pickled Golden Toad captured in the wild!"
John replied in an instant without thinking – "Well what was it doing balanced on the arm of this chair?"
He looked up. Standing in front of him, holding up one dust covered finger, stood Sherlock Holmes.
Sherlock reached down to help John up from his position spread-eagled on the floor and smiled. As John stood up, Sherlock looked around.
"Look at the state of this place! If you had to keep it, you could at least have cleaned up!" All Sherlock saw next was John leaning back with one shoulder.
This time, it was Sherlock's turn to be helped off the floor.
"What was that for?!" He yelped indignantly.
"It was for two years, and three hundred and twenty one days", John snarled.
"Oh... yes, um, John. I'm... sorry for what you went through. It was unfair. However, there were some people that I needed to convince I was dead, and I must say it worked rather well! I was able to finish off a few cases in other, more low-profile countries and we won't ever be bothered again by Mori-"
"SHERLOCK! Listen to me!" John strode across the room and grabbed the skull, brandishing it at Sherlock angrily.
"I am listening John! If you would listen to me for one more minute, I was going to tell to you that I did it for you. To save you."
The silence was deafening. John lowered the makeshift club.
"...What?"
"I told you! Moriarty had gunmen trained on you, Mrs Hudson and Lestrade. Unless I jumped and completed his 'fairy-tale' then he would have killed you. My death was the signal to call off the gunmen." Sherlock looked down, slightly embarrassed.
John's eyes glistened and his shoulders slumped. He looked small, lost and alone.
"Oh Sherlock. I thought you'd left me. I convinced myself that you were a selfish bastard who couldn't be bothered to think of a way to escape. Just promise me one thing. One thing. Next time, just let them kill me. I don't ever want to lose you again."
Sherlock smiled slightly.
"John, you know I never would."