Despite how he might look, standing next to Sherlock Holmes all the time, John Watson was not stupid. He didn't have Sherlock's amazing powers of observation and deduction. He didn't have the wits to go head-to-head with Moriarty, the world's most dangerous criminal. John only looked a bit thick because anyone who walks in Sherlock's shadow can never look good – unless it came to tact. Then, no one could ever fail.

No, John wasn't stupid and, if there was anything he knew, it was Sherlock. He'd lived with the man for over a year, and loved him for a lot of that time. He knew Sherlock like no one else, except perhaps Mycroft, but he didn't count. He knew Sherlock better than Lestrade did, better than Mrs Hudson did; he might even dare to venture that he knew Sherlock better than Moriarty.

And that's why John refused to believe it.

Sherlock was a good actor, but there was no way he'd acted for the entire time John had known him. To have set up Moriarty, he would have had to plan every single crime. He would have had to have either employed or manipulated Irene Adler, and then acted through the entire thing. And if he was that clever, then he might as well have solved all the crimes by a glance at a man's footprint, because both acts would have had the same level of brilliance.

And, John added to his conclusion, there was no accounting for Mycroft. Mycroft surely wouldn't have agreed to go along with his brother's act, and Mycroft had to be who he said, simply for the influence he had over government matters. The man had personalised the message on the cash point John was using, for God's sake! He had every telephone ring as John walked past – including the public ones. No, the idea that Mycroft was fake was even more impossible than the idea that he was real.

John used these points as his logical argument against the idea that Sherlock had lied to him like he would a shield against the nails Moriarty was nailing into Sherlock's coffin. Even as Sherlock stood on the rooftop and told John over the phone that it was all a lie – every day of the past one and a half years hadn't been true – John clutched at these facts, holding them close and tight. Sherlock couldn't be a lie, because he was the foundation John had built his life upon, and without him, it all would crumble.

The day after the funeral, John sat motionless in front of the headstone. His legs were crossed, his eyes fixed on those two dreadful words. Two words that should never, ever be on a gravestone.

Sherlock Holmes.

Before all this happened, John would never have admitted that he'd rather anyone's name be on a gravestone as long as it wasn't that one. Lestrade, Mrs Hudson, even himself; all were preferable to losing Sherlock. But now… he was grieving over his best friend, his flatmate, and the man he loved, and he didn't give a damn how horrible that admission was.

His eyes were dry; he'd done all his crying in the days prior to the funeral. He didn't think he'd ever cried so much in his life, and he probably never would again. But Sherlock tended to have that reaction, to make people do things they otherwise wouldn't do.

His mind was racing with possibilities and need. The possibility that there was something John had missed; that somehow Sherlock was still alive. And need; need for him to come walking up to the grave that very moment and call John an idiot and explain it all.

Because Sherlock had to be alive. John had watched him die with his own eyes; had seen the blood seeping out onto the pavement. Despite that, he still couldn't believe that such a brilliant man could do such an ordinary thing like dying.

The thing that stuck in his mind was why would Sherlock kill himself? There were few logical explanations that John could think of. Sherlock hadn't been in such an emotional state that he would have seen death as the only way out of his predicament. Whether he was a genius or a fraudster, he had the skill to move to another country and recreate his identity. There was no need for him to die over what was happening with the police.

They found Moriarty's body on the rooftop, although when they told him John had been too consumed by his grief to care. He'd known anyway, right from the very beginning, that Moriarty was involved; his body being only metres away told John what he already knew.

The authorities couldn't decide whether the criminal (or actor, as they'd said) had killed himself or been killed by Sherlock, who'd then made it look like suicide. John didn't care either way; the bastard deserved far worse than what he got.

But why had Sherlock jumped? What was so bad that he'd kill himself – and discredit himself with John while he was at it? John was not naïve enough to believe that nothing was worse than death. There was a list of things. Extreme physical torture. Extreme psychological torture. The death of those you cared about – a pain John was currently experiencing. What Moriarty had done – tearing down Sherlock's life so that he was a fugitive – was also, in a way, worse than simply shooting him outright.

But what had pushed Sherlock over the edge? His body had shown no signs of fighting, let alone the brutal marks torture would leave. John knew that he'd not left Sherlock alone long enough for Moriarty to mentally break him to the point of confessing he was a fake and then killing himself. The idea that maybe Sherlock had died because John himself had been threatened was one he'd touched upon briefly, but pushed away. Sherlock had only recently found the courage to call John 'friend'. He doubted that anything short of blowing up the entire city of London would convince Sherlock to do what he'd done.

So that left him – what? It didn't leave him a lot. A threat with immediate danger that was worse than death. Maybe killing someone Sherlock cared about, but unlikely. Perhaps Moriarty had threatened to paralyse him, disable him to the point of helplessness, or somehow damage Sherlock's intellect. It would be the ideal way to threaten him; if Sherlock would hate anything more than dying, it would be having the most amazing intellectual abilities but being trapped in a vegetable body, or to be stopped from using his brains by some other means.

Yes, that was definitely a possibility, although it didn't explain why Sherlock had told John that he was a fake.

John buried his head in his hands. He knew there was a piece he was missing, but it would take impatient explaining by a high-functioning sociopath before John realised what it was.

And now there was none of those around to help him out.

He didn't know how long he sat there until Mycroft found him. He did know that by that time he was cold and wet due to the drizzle that had started at some point. John couldn't remember when that had been any more than he cared. What did it matter if he got a cold or pneumonia or something deadly; he was sitting in front of Sherlock's gravestone. Nothing in the entire world mattered anymore.

"It's your fault," John said, when the man came and stood beside where John was sitting. He had an umbrella over one arm, but despite the weather it remained unopened. "You killed him."

He knew deep down that he was being unfair; Moriarty had killed Sherlock, not Mycroft. Mycroft was Sherlock's brother, and he was grieving too. But John didn't care, because he was grieving more, and Mycroft had made a mistake. Mycroft had made a mistake that cost Sherlock his life.

It was a bit ironic; Sherlock had commented more than once that Mycroft was the British Government. With a twitch of his finger, Mycroft could wipe out hundreds of thousands of people. John wouldn't have been surprised if one day he'd opened the paper to see the headline "India wiped out in nuclear explosion," and for Sherlock to say that it'd happened because Mycroft had a hangover.

And it was ironic because Mycroft, who had all that power, had made a mistake that had killed Sherlock. His slip up had killed only one person that mattered (the only person that mattered) and John wished that it had been anything else but that. Hell, Mycroft could have 'accidentally' nuked the rest of the world and John wouldn't have cared much; if only Sherlock was still alive.

He'd expected Mycroft to protest his innocence, but he didn't. Instead, he simply stated, "I know," and gazed at the headstone alongside John.

"Your mistake cost the life of the most brilliant man I ever knew," John wanted to say to Mycroft. "It cost the life of the man I loved."

But he didn't say it, because Mycroft knew. He knew what it had cost, and he knew John held him accountable. Anything else was just words in the air; useless and unnecessary.

"He didn't do it."

"Didn't do what, John? Didn't kill himself? Because I think we can all agree that that is what definitely happened."

John glared at Lestrade, who'd come around to visit him now that he'd finally managed to return to the flat. "You know exactly what I'm saying."

Lestrade sighed. "I know, John. I'm not entirely convinced that he was a fraud, but you have to admit that it looks bad."

"No, it doesn't!" John's temper had never been one-hundred per cent contained, and it exploded now with vengeance. "It looks exactly the opposite, and you know it! Sherlock didn't give a damn what you all thought of him; he knew you lot all hated him and he revelled in it. He never went out of his way to be nice, and insults came to him more naturally than breathing did. If he'd wanted to seem like such a hero, he would have basked in the attention rather than put people down and give so much cheek to a judge that he ended up in prison."

"It was an act, John," Lestrade said, but his voice sounded uncertain. "He was trying to put us off the truth."

"There is no 'truth'," John spat. "I should know – I lived with him. Don't you think that if he'd been doing all this – including researching the background of complete strangers, by the way – then I might have picked up some hint of it? Something to make me a little suspicious?"

"He had you fooled, John-" Lestrade tried to say, but John cut him off.

"No, he didn't! There is no way he could have set up all those crimes, and there is definitely no way he could have done it without letting me know. And," he said, as Lestrade opened his mouth, "even if he had, that would have required even more brilliance and planning than Moriarty."

"You mean Sherlock's character."

"Call him what you will," John said angrily. "My point is, if Sherlock was that clever, then wouldn't have needed to fake solving crimes like he did anyway, because he would have been able to for real."

"I don't think I quite get what you're saying."

John sighed in frustration. "Look at it this way," he told Lestrade. "Consider, just for a moment, that this entire thing was set up by Moriarty, and Sherlock is, in fact, who he seems to be."

"Was," Lestrade said.

"I beg your pardon?"

"Was. And Sherlock was, in fact, who he seemed to be. You're talking about him in present tense."

"Yes," John said, temporarily thrown. "Was." Then he cleared his throat and continued. "If Moriarty set this up then, despite the fact that he's also deceased, he beat Sherlock. The whole world thinks that he's a dead liar. That has got to take some brilliance. But," he interjected, as Lestrade seemed about to interrupt, "consider that Sherlock was a liar. Because, believe me, I have considered it. I've considered that a lot. And it doesn't add up.

"If Sherlock was a liar, then he would have had to come up with all these ideas. He would have had to plan it down to the last detail, all the while ensuring he was never regarded in a suspicious light. He would have had to arrange for all these murders and crimes to be carried out, still without arousing suspicion. Then he would have had to come up with logical explanations as to how he found the criminals which, in case you haven't noticed, is exactly what he did when he solved them, just without the extra effort."

Lestrade wasn't interrupting anymore; he was listening intently. John was heartened by this, and continued. "Sure, sometimes we took his conclusions on his word without asking for an explanation. But a lot of the time he'd tell you how he knew something, and what he'd observed to lead him to that conclusion. He was almost never wrong. Every explanation had logical sense, and there was never another possible answer. When he said he didn't make guesses, he wasn't lying, because guessing implies there is a chance that he'd be wrong, that there'd be another explanation. There never was, and you know it. Even if he had arranged all this, it would have required massive intellect. The amount of intellect that would have also allowed him to solve the crimes without already knowing the answer."

Lestrade rubbed his eyes, as though wary. "You make a good point, John," he said.

"I know I do," John told him. "Because I'm right. Because Sherlock was genuine."

"So you keep saying."

They were quiet for a while and then John said, "I know why you don't want to admit that Sherlock might have been innocent."

"Do you? And why's that?"

"Because then you have to admit that, if you hadn't let yourself doubt, if you hadn't gone for an arrest warrant, then Sherlock would still be alive."

Lestrade left not long after that. John didn't care. He didn't care that Lestrade probably wouldn't come back, and he didn't care that he didn't believe Sherlock had been good after all. John knew the truth, and he didn't need anyone to tell him.

He wanted to move out of the flat, but he'd grown too attached to Mrs Hudson to do it with a clear conscience. After all, she'd regarded Sherlock sort of like the son she'd never had, and John knew that the fondness in her heart stretched to encompass him as well. He didn't want to make her lose them both.

He settled for moving next door, to 221A. It was weird, somehow wrong, because his home was 221B and nowhere else, but he couldn't stand to go back there. After all, it wasn't home without Sherlock. Nowhere was.

And so, with a new flat and a broken heart, John would attempt to put his life back together. It would be like fixing broken glassware with duct tape and superglue, but he'd try all the same.

Because what else was there to do?