Sherlock had always been surrounded by death; it was part of his job.
Except he seemed to have forgotten that it applied to everyone, including his friends.
He supposed it had always been there, hovering in the back of his mind, that niggling voice that warned him it wasn't going to continue this way forever, that it couldn't.
Because time touches everyone, and that's something that even Sherlock Holmes couldn't change.
Mrs Hudson was first. It was expected, she was the oldest, and it was inevitable.
Heart disease. She was in and out of the hospital for a while, couldn't make it up the stairs to yell at her boys and tell them she wasn't their housekeeper.
She passed away in her sleep one night at Baker street. It was the way she would have wanted it.
She was cremated, her ashes kept in an urn on the mantelpiece in Baker street, which she had left to them in her will.
Next to the skull.
Sherlock missed having someone to natter at him about shooting holes in her walls, and putting that on his rent, and tutting about the state of the place and the mess.
They both cried for her.
Time passed. They grew older and weren't as capable of running around on cases, jumping over rooftops to catch criminals. They still went to crime scenes, Sherlock still annoyed Anderson, who was still inept, Sally still called him Freak, Lestrade still sighed and looked exasperated.
But there were no more midnight chases, tackling criminals off of roofs, or getting kidnapped to do research.
Mycroft died next. Cancer.
Sherlock visited him at home, wasting away in his bed, and still commented on his diet.
John was unnerved, but they seemed content with it. John understood how important normality was.
His death was slow and painful, padded by drugs that made him sleep most of the day and forget his own name at the worst times.
Sherlock didn't visit often, but was there at the end.
Mycroft was buried in the Holmes cemetery on the grounds of the mansion John had never seen before. Sherlock was anxious throughout the funeral and seemed to want to be anywhere but there. John didn't blame him.
Later, Sherlock informed John that he was never, ever, going to be buried there. Ever.
There were too many memories at that house, and even after death, Sherlock didn't want to spend any more time there than he had to.
Lestrade retired, and so did Sherlock and John along with him. Sherlock didn't have the patience to deal with any other officers, and they felt rather the same way towards him.
With nothing keeping them tied to London, Sherlock and John sold the flat to Molly and her husband, who were adopting a baby. Sherlock and John went to visit after she was brought home. They named her Olivia Shirley.
They found a large home in the countryside, plenty of land and room for Sherlock to continue his experiments.
A couple months after they had moved into their new home, John received a phone call from the hospital. Lestrade had been shot.
They rushed over to see him, finding out that he had stopped the rape of a young woman and had been shot for his troubles, but not before giving the culprit a concussion, rendering him unconscious and ready for police pickup.
But his aorta had been nicked, and there was nothing more they could do for him.
He was buried the following Monday, only a simple service.
Sherlock and John stood at his grave after everyone else had left.
Sherlock knelt down and traced out the letters of his name, a name that he hadn't even known for the first couple years after meeting him.
John pretended not to see as Sherlock leaned his forehead against the cool granite and cried.
Sherlock pretended not to see the tears tracks on John's cheeks as they left the cemetery.
Sherlock traded his more dangerous hobbies that involved chemistry for a new one- beekeeping.
John would watch him from the kitchen window as he stayed outside for hours, observing their patterns, watching their movements, and sometimes, John swore, as he talked to them.
John wrote a book, hoping that it would for once and for all, put the rumours to bed that they were a couple. He knew how unlikely that was, two ageing men who'd never been married, still living together after all these years.
But to be honest, he didn't mind it all that much.
Because people would talk. They did little else.
John had to return to his cane, Sherlock not making any comments this time, as he knew it was needed rather than psychosomatic. Likewise, John didn't comment when Sherlock started wearing glasses and no longer bound up the stairs like a rabbit, instead taking them one at a time like a normal human being.
Sherlock realized that's what ageing was. It made people human.
He wasn't fond of it.
It had been a sort of morbid unspoken competition, which of them would die first.
Secretly, Sherlock had his fingers crossed that it would be at the same time, perhaps carbon monoxide poisoning in the middle of the night.
John knew it would be him, because he hadn't told Sherlock yet. He knew Sherlock was only denying the signs, that he didn't want to believe what his stupidly logical mind was telling him.
But soon he couldn't walk, his vision faded, and he couldn't control his limbs in any sensible way, and Sherlock could no longer deny the invader that was taking his best friend.
He couldn't decide whether to laugh or cry when John died from a stroke in his sleep, showing that damn brain tumour who was boss in the end.
He settled on doing both.
John was buried in the plot that they had gone together to pick out, side by side, underneath a red oak tree.
Sherlock sat at his grave and cried for him, as John had once done at his so many years ago.
He awoke in the morning and decided john would not be pleased that he had slept there the whole night, at his age, and headed home, somewhat stiff, and knew that John was smiling and thinking I told you so. And despite his best attempts, Sherlock smiled at that thought.
But the house they had bought together in the country was too empty now that he was only one, and even the skull that still took up residence on the mantelpiece, next to Mrs Hudson, could not fill the void that John had left.
He talked to her sometimes, telling her how unfair it was that he was to be the last one.
He knew that everyone had expected him to die young, leave a nice corpse, cause his own death by doing something reckless. He laughed bitterly at them now, Sally who had died a couple of years ago in a car accident, Anderson who had died of pneumonia in a nursing home, even Molly, who'd caught some strange disease from the morgue and succumbed to it, leaving her husband to raise Olivia alone.
Sherlock told Mrs Hudson all this, and when the tears finally cleared, he went outside to play with his bees.
They had been a comfort to him, surprisingly predictable and good natured, which was part of the reason why Sherlock liked them. He liked that they shouldn't be able to fly, and yet did. He'd even written a book on them, which had created quite a buzz in the beekeeping world.
He let them crawl on him, delighting in the feel their feet made on his skin.
The tears welled up unexpectedly, and he reached to wipe them away, disturbing one of his little friends in the process.
It stung him.
"That was hardly necessary," he told the little bee, who was now going to die because of his recklessness.
Considering his recent hobby, Sherlock had only been stung once before, which he'd found rather amusing, but had worried John, citing all sorts of studies about allergic reactions.
Sherlock shook the bees off, shooing them back into their enclosure and headed for the house.
Sherlock both hated and loved that John was right and would have laughed had he been able to draw in breath.
But he was in the throes of anaphylaxis, and it was unforgiving. He collapsed just outside of his house, feeling terrible for dying here when he knew that Molly's husband was coming over the next day with Olivia for a visit.
But he knew better than anyone that time touches everyone, even Sherlock Holmes.
Besides, he was part of a pair, Sherlock and John, Holmes and Watson, and he could hardly leave John alone in the matching plots under the red oak tree.
So he smiled.