A/N: He - they - have to depart like the rest of us some day. Overflowing, hopefully in-character angst. My heart was heavy, to say the least, while writing this.

A little bit romanticized. I'm not cruel enough to write the reality.

As always, I do not own the cover image. Please PM me if you want it taken down.

Reviews are loved. Constructive criticisms are worshipped.

Final Mercy

Sherlock flatlined today.

It was his fiftieth birthday. Greg was by my side when it happened, and the good detective, despite his attempt at self-control, turned away in tears. "It isn't fair," he muttered to me incoherently, and left the room.

Once upon a time, I had agreed with Greg. Indeed, it hadn't seemed fair. Nothing had seemed fair where Sherlock Holmes was concerned: the singular Sherlock Holmes, the one and only consulting detective in the world, who could solve the planet's most convoluted cases in the blink of an eye.

Having been exposed to and spoiled by his genius for far too long, I used to scorn those who babbled on about the justice of Fate. "She has a way of maintaining balance in this world. Brilliance comes at a costly price," they said.

I always dismissed these talks as utter bollocks.

Fate used the last five years to prove me wrong.

Five years ago, Sherlock called Molly Hooper "Margaret" for the first time.

He gave himself a little smack on the forehead and corrected it immediately, of course. But a few days later it happened once more, and again in another week.

Molly called me, and we talked for an hour. It was the longest conversation I've ever had with anyone on the phone. I never knew how persuasive and persistent she could be until then.

It wasn't easy, but we urged Sherlock into Bart's for a detailed examination. He wasn't cooperative, and derided his doctor many times during his medical interview. It took weeks for the results to arrive.

It was an aggressive form of early-onset Alzheimer's Disease.

When his doctor first revealed it to him, my flatmate laughed in his face, and proceeded to vehemently deduce the ugly side of his entire family history. Sherlock stormed out of the hospital before the doctor could show him his brain scan files, and he composed chaotic tunes in the flat, until Molly showed up at our door with reddened eyes, his files in her hands.

Sherlock and I examined the files together. I was speechless and nauseated, and lay myself on the sofa. Sherlock leafed through the files again and again with a critical eye, and said not a word. I noticed tremors in his hands, the severity of which elevated each time he repeated his professional analysis.

Molly repeatedly excused herself to use the water closet, and her eyes were redder each time she returned.

Mrs. Hudson joined us, too. She made a delicious meal for dinner, but none of us ate more than a few bites.

After Molly left, Sherlock curled on his chair and was silent and immobile for five straight hours. When it was well past midnight and I tried to urge him to bed as indifferently as I could manage, he said to me suddenly,

"John, why isn't euthanasia legal in this damned country?"

Mrs. Hudson and I took turns to watch him very closely for the next week. For the first two days, he was in a daze. Then he began taking on a plethora of cases, cases that he would've dismissed in the past for being too banal.

He worked day and night, and avoided sleep as much as he could. I helped him.

Four years ago, Greg brought Sherlock a badge, flowers, and a huge stack of cards.

Sherlock was not amused. "Is this your friendly way of firing me from your job?"

"Sherlock..." Greg began, but he choked on sentiment and could not go on. In the end he stuffed the cards into Sherlock's hands and said simply, "Read these, will you?"

After Greg left, Sherlock tossed the cards to me. "Burn them."

He locked himself in his room and played his violin for the rest of the day.

I spent the entire afternoon reading these cards. They were gathered from fans all over the world, in response to a rally on the Internet started by theimprobableone, an avid follower of Sherlock's blog. Some expressed their condolences at Sherlock's deteriorating condition. Others thanked him for a glorious crime-busting career. All wished him well with their petty, rambling words that meant next-to-nothing even to me.

There were cards from the Scotland Yard as well. These were mostly plain one-liners that were worth all the fan-mails combined.

There was one from Donovan. "I don't give a fuck what others say; to me you'll always be the most annoying freak in the world."

There was another from Greg. "You bastard. I won't forgive you for leaving us early."

There was a third from Anderson. "Come back to the Yard some day for a visit. I'd want to hear of any new insults you've devised and try out my new counter-attacks."

I saved those three and burned all the others in the furnace. They made for a very pretty flame.

Three years ago, Mrs. Hudson moved away.

Her hip was deteriorating quickly, and Sherlock's new habit of violently destroying items in the flat had agitated her nerves. She was reluctant to leave, but her daughters insisted upon it, and they took her away to the south on a fine afternoon.

"Call me every week and let me know how darling Sherlock is doing, won't you?" she said as she stood in front of the cab, her wrinkled hands trembling as they held my fingers.

I hugged her and nodded. I didn't know what else to say.

I watched her cab until it disappeared into the horizon.

That night, I was in no mood for fine cuisine. I made some instant noodles for dinner. Sherlock grimaced as he ingested the ungodly food, and spat at me with contempt, "What the hell is wrong with Mrs. Hudson? She never cooks this garbage."

I said, "Mrs. Hudson said goodbye to you and moved away a few hours ago."

"Oh," his features fall, and he lays down his utensils. "I'm going to my room. I'm not hungry."

The new landlady was nothing like our old one. She looked upon everyone with spite, and gossiped constantly to her acquaintances about the crazy, mentally deficient man in her flat who would throw fits of rage at the most unexpected hours. I had tried diligently to alter her views, but after fifty or so futile attempts, I gave up.

Sherlock still wondered where Mrs. Hudson was, every time our dinner was less than satisfactory. I told him repeatedly that Mrs. Hudson had moved away. His expression of disbelief and hurt were so similar each time, and despite having seen it hundreds of times at least, I was never immune to it.

Each time he refused to eat and went up to his room to sulk, I would curl on the couch and stare at the ceiling, asking "Why?", silently and repeatedly, to cruel, cruel Fate.

I thought inadvertently about how it would all get worse from here.

Two years ago, we attended Molly's funeral.

A man Sherlock had convicted, one from Moriarty's long-destroyed network, was released on parole. He tracked her down, gunned her in front of Bart's after one of her late-night shifts, and fled.

When they found her, she lay in the spot where I had once seen Sherlock lie. Blood spattered the pavement.

Sherlock stood in front of her grave and didn't move for hours.

I watched him initially, but it was a moist day, and my arthritis was acting up. I went into the church and sat, and dozed off.

I later received a phone call from Greg. Sherlock had gone to Scotland Yard and, from nothing but the files that they've collected of the crime scene, deduced the murderer's whereabouts and closed the case.

It was the last case that Sherlock ever solved.

I went home and found Sherlock staring at a photograph. It was a photograph taken in Bart's of Mike, myself, Sherlock, and Molly. It was the only photograph that he and Molly ever took together.

I walked up to him and asked, "Do you remember her name now, Sherlock?"

Sherlock raised his head and stared at me, and his eyes were hazed.

"Molly. Not Margaret. Molly."

One year ago, Sherlock disappeared.

He said he was going for a quick stroll down the block; the air in the flat was too foul for him. I nodded and said nothing of it. His tantrums were getting worse, and I was needing a bit of a break.

He didn't return.

It began snowing.

I put on my thickest jacket and rushed into the blizzard. I screamed his name. I asked every passerby if they'd seen him. I searched in the blizzard for hours, before I finally found him sitting by the Thames River, staring hollowly into the dark waters.

"What the hell do you think you're doing!?" I rushed to him and threw my jacket onto him, feeling rage boil my blood.

He turned to me and blinked.

"Who are you? Why are you angry at me?"

My blood boiled no longer. I froze. I stared at him and laughed hysterically. "You're kidding."

He wrapped my jacket tighter around himself and shook his head.

I lost it.

For every moment in the past four years I was shadowed by this fear, but I had never left my place beside him, never complained, never felt a moment of anger for all the unreasonable things he'd done, because I knew it was all the disease's fault. But at that instant I could not hold it in anymore, and I crouched and punched him and screamed at him to stop this nonsense, to call my name, to bring back the old Sherlock and to end this terrible game of pretend!

I dropped to my knees and, for the first time in decades, sobbed into my palms.

Sherlock did not retaliate, nor did he ever remember my name. He placed a hand on my shoulder and stayed silent until I was ready to take him home.

Two weeks ago, Mycroft came to visit.

He still seemed as impassive as ever, and he still carried his umbrella. But the wrinkles in his forehead have deepened considerably since his last visit, and his hair was white as snow.

He brought a present for Sherlock. Sherlock's old pirate-sword.

Sherlock could no longer speak coherently, but the present had made him happier than I have ever seen him in these past few months. He took the sword and danced daringly around the room and then up the stairs. I watched his bumbling movements almost with a smile, until I thought of Fate and Her arts and my smile dropped.

God, this toddler in a man's body had not so long ago been the most brilliant man in the world. She'd given him formidable intelligence. She'd given him not long, but considerable longevity. But at this moment of his life, She'd stripped him of everything he ever was, and deprived him of all dignity and grace. She didn't even allow him the luxury of remembering anything that had once been important in his life.

God, Fate is so cruelly fair that it hurts.

Yesterday, Sherlock crashed down the stairs during one of his pirate adventures.

I rushed him to the hospital. He was in a coma.

Mycroft came to see him, but wouldn't enter his room. He sat outside and smoked, and wouldn't eat.

Greg was in the room with me, and we took turns watching Sherlock's electrocardiogram. Sherlock's bandaged face seemed ghastly pale and eerily serene. We thought it would take a miracle for him to wake up again.

And by Gods, there was a miracle.

I was dozing off by his bedside when his voice woke me.

"Lestrade, I see you've finally ditched the wife, what is it, two years ago? Well, I'm sure ashamed it took me this long to notice."

Greg jumped from his chair and called for doctors. I rushed forward and clutched tightly onto his right hand.

There was a characteristic Sherlockian smirk on his face, as his eyes scanned me with a lucidity I haven't seen in far too long. "Good God, have you been drinking more than usual lately? I wouldn't advise it. You know what it did to your sister better than I do."

I saw the flush on his face and I knew that this was the last moment before his departure. There were tears in my eyes, but I wiped them away. This moment of lucidity, this last moment of dignity, was a gift from Fate: Her final mercy. And I was thankful for it.

I squeezed his hand and chuckled. "Welcome back, Sherlock."

His fingers vibrated weakly in my palm, and he breathed his last, genuine sigh of relief.

"John."