Inspired by a picture of Sherlock cradling John's body.
There will be a part two.
…
In the darkened alley, Sherlock sees absolutely nothing but the gun in Moran's large, tattooed hand. In an instant, he observes everything about it; the make, the model, where it's made, even the exact measurement of the barrel and the brand of silencer attached to it, but the one detail he cares about in this moment is where it's pointing- straight at John Watson's heart.
Before he realises it, Sherlock's feet are moving, and he is jumping out to tackle the ex-sniper to the ground. Only when he's sure the man is immobilised with a teeth-shattering punch to the face does he return to his feet to face his doctor, whom he has spent three long years living in hell-holes, skirting through war-zones and generally doing whatever it took to weed out Moriarty's network for. He smiles somewhat sheepishly.
John is unsteady on his feet, eyes wide at the sight of him. The familiar silver cane topples to the ground, and Sherlock puts his trembling down to the shock of seeing his best friend back from the dead.
"Sher-sherl-" And then the man crumbles, and the consulting detective catches him and gently lowers him down to the ground. John is barely conscious and still shaking, and for the first time, Sherlock notices a dark liquid seeping through his oatmeal jumper.
Blood.
…