Note: I warn for character death and tragic endings. Consider yourself warned. Pretty much the sole purpose of this is to make you cry.

John's respiration sounded terrible, like a bellows with a hole in. Sherlock had heard that sound once, when he'd visited a blacksmith's shop. There'd been a fight. A shovel had ruptured the bellows. It had sounded better than John's lungs, because the broken wheeze of the bellows hadn't made Sherlock want to vomit.

"I thought." John laughed a little, with what breath he could spare. Stop it, Sherlock wanted to beg. And, Please, don't stop laughing. Don't let it be your last. "I thought Afghanistan."

"I thought Moriarty," Sherlock admitted, bowing his head down alongside John's till their hair wove together.

"Yeah?"

Sherlock nodded. "When you grabbed him, my heart stopped. I thought you were a dead man."

"Should've run, you fool." It wasn't speech. It was a word-shaped sigh. John's back was to Sherlock's chest; their faces pointed the same way, laid alongside one another. Sherlock was glad, because he could squeeze his eyes shut on the stab of grief without being observed. I'm sorry, John. I'm so sorry. I should have been faster.

But he couldn't say it. John would not thank him for wasting their last moments on regret. Sherlock would have the rest of his life for that. This time right now, it was the last thing he could give John. He kissed the golden-haired temple. If I had run, this moment would have happened four years earlier.

Why should he keep that in his head? John should know. He deserved to know Sherlock would have given anything for those four years. So he said it out loud.

"Don't," gasped John. "Don't make me cry." It wasn't a plea for emotional dignity. Crying might actually kill him. He was struggling for air as it was.

Ten minutes. If they weren't buried in the bowels of the London Underground, medical help would've been close enough to stop this. Sherlock was familiar with the poison John had been administered. So was John; there was no shielding him from the knowledge of his remaining lifespan. Ten minutes before the toxin reached his central nervous system and paralyzed autonomous function. His sight would blur out as his pupils dilated. His mouth and eyes would go dry as his endocrine system shut down. He would cease breathing. His heart would stop. John would stop.

In ten minutes Sherlock would live in a world with no John in it.

He couldn't do it. And so it was easier to forget that it would happen. Sherlock had ten minutes. After that...there was a void. He would fall across it and land on the other side in a new world, and find out what it was like.

The criminals' final 'fuck you' to Sherlock Holmes. He'd solved the case. He'd captured them. He'd been too late. Too early. Should have let them run.

John was so warm in Sherlock's arms. Warm and soft with layers of clothing and hard with layers of muscle and so very soft with weakness, vulnerability, fear, love. "I don't want to die," he confessed, nestling closer. "Sad, yeah? I'm a soldier. Supposed to be graceful in the face. But I don't. I don't want to go. I don't want to leave you."

"I don't want you to leave either." Truth was a brutal tool, the most savage of all methods of accessing the innermost self. Sherlock had only ever used it as a weapon, but they'd run out of time for the kinder ways. It was more important than the pain of honesty, to feel their souls lying naked against each other this one last time.

Would it have been better, Sherlock wondered, if he could have kept up his facade? His detached, unemotional, you won't leave anyone behind who can't stand losing you facade. Would John have liked it better to know that he would be mourned, or would it give him peace to think that at least his death didn't hurt anyone?

It didn't matter. There was no pretending he was the man he'd been before Doctor Watson hobbled into his life. No pretending that Sherlock wasn't bracing to die in nine minutes, to have his soul cut to scrap with an acetylene torch.

He'd never died before. John had, at least once. And he was still afraid of it. John was the bravest man Sherlock had ever known. If he was scared, Sherlock suspected he should be terrified. He squeezed John to him like a huge pliant teddy bear, turned him a little so they could look one another in the face. "I would go with you, if I believed in life after death."

John smiled and reached up to touch Sherlock's face with unsteady fingers. "I kind of wish I did, right now. Would it be better, you think?"

Sherlock shook his head helplessly. "If you were there, it would be." He lowered his head till their foreheads touched. "Can you imagine?" he asked in a whisper. "An eternity of us. Stone boring, d'you think?"

John tried to laugh again, a little hitch that hooked into Sherlock's heart and tore out with tiny barbs. "We can't be boring. We'd be the terrors of the afterlife. You could." His chest spasmed for breath. "You could hunt all the criminals no one ever caught. Jack the Ripper. Zodiac. The Tsars' treasure."

"John." A deduction seized Sherlock with a sensation like hugging a kerosene heater, shot through with the most exquisite warmth and agony at once. It wasn't fair. This should be a Christmas gift. A birthday present. A discovery for a grey day when they were huddled against the world, content in one another. "You've been researching cold cases. You never told me."

John's neat white teeth flashed in a bare smile. "Was saving it. For a rainy day."

Then his body crushed a gasp from his lungs as it locked up in protest against some new barbarity. Sherlock gathered him up, face aching with the effort of not twisting in anguish at the panic filling those blue-brown changeling eyes. His placid, steady John should never look like that.

Five minutes. John's heart was going tachycardic. It hurt, Sherlock was given to understand, with the unique pain of a body being forced into a rthythm not its own. "Sight's going," John whispered, when he could breathe again. "Can't see you properly. You're fuzzy."

"You know what I look like." Sherlock stroked his hair, and didn't have to hide the wetness gathering on his lashes.

"But I won't see you again. I want to store it up."

"It's alright." I'm the one who needs to remember. So little time now. Time to fit in all the things he would never say or hear. "John. You know that song I play sometimes? In the middle of the night, when you want to yell at me for waking you but you're afraid I'll stop?"

John's head shifted in a nod against Sherlock's shoulder. "It breaks my heart," he confided. "Never told you. So beautiful, but it hurts so much. Always so afraid," the hitch this time was tears, despite his staunchest efforts, but lacrimation was going offline. John couldn't cry anymore. "Afraid for you, that you felt like that." His hand stroked over Sherlock's arm and shoulder. Fear was back in his eyes, but this time for Sherlock; worry for how he would be without someone there.

Sherlock shook his head insistently. John couldn't go thinking that he was abandoning Sherlock. That couldn't be his last thought. "No. No, John, no. That song was for you." He was, he discovered, nuzzling over the curves of John's face, unable to stop from feeling everything he could. "That song was you. I played it so no one else would hear. You were always so sad, my dear John. So angry. So strong and gentle. Life has betrayed you so many times, hasn't it, and I played it so that you would know I knew and I would never, never..." This wouldn't do. Sherlock was losing track of what was only in his head and what was coming out of his mouth, when every syllable needed to be etched clear in his memory. He lunged for self-control. "You were safe with me, John. Always. I know I, I could get us into such stupid situations," like this one, he squashed that thought savagely. "But I wanted you to know I would never betray you. It was only for you."

Precious seconds passed in which neither of them spoke, only clung for dear life.

"You never betrayed me," John finally breathed. "I followed you. My choice. So worth it." He pulled; Sherlock obliged him by propping him up straighter. It couldn't make any difference now. "I'm so proud, Sherlock. Your beautiful mind. And. And. Greg said. You were a great man. And one day he hoped, you might be a good man. And you are, Sherlock. You are."

It was a hell of a speech for a man whose lungs were giving out. Exhausted, John leaned helplessly into him for another few eternities while Sherlock's hands stroked over him, memorizing every detail of John in his arms.

"Sherlock. Hum it?"

Sherlock smiled, tilted John's head up to place a chaste kiss on his lips, and obeyed.

He was still humming when Mycroft finally got there, John's fading warmth tucked close against his side.