For patster223 and sakoratay, who make me so very happy.

Disclaimer: I do not own Sherlock.

Dark alleys lay together like a maze in central London, weaving through each other in patterns obviously unknown to John from memory but so well mapped inside Sherlock's own. Directions zoom across his mind as if he's looking at them on a screen and it's so damn helpful. Everyone could do it if they truly wanted to, but people are so stupid.

John bumps into Sherlock's back when the latter suddenly stops to consult his mind-map. "Oof," he breathes, then, "Sorry, Sherlock."

Sherlock ignores him, eyes popping open. "Through here, he'll have gone through here," he loudly states, beginning the chase once more.

"Right, good," John nods, always right behind him. The thought makes Sherlock smirk with a rush of enjoyment.

They don't make it very far before the man they're tailing jumps out from behind a pair of bins with a long silver knife, too close to John.

A split second has Sherlock frozen when John yells out in what he would categorize as pain. Then the second is over, and John throws a punch, lands it, and removes the knife from their criminal's hand. Long legs don't fail the man, however, as he jumps back to his feet and is on the move once more.

"Are you all right?" Sherlock yells behind him, still in pursuit.

"Just a little nick! Keep after him!"

Sherlock doesn't need to be told twice, but five minutes later and the trail has gone cold. Sirens are heard in the distance, confirming that Scotland Yard finally made it around after Sherlock called them 13 minutes ago. The man they're after is wanted in connection to a young girl's murder, so he supposes they'll have pulled out all the stops concerning their police force.

It doesn't keep Sherlock from cursing, however. "He was right here! Just a little faster and he would have been right here!" He's shaking the air with clenched hands.

John is nodding a little too much, backing slowly against the wall, hunched over as Sherlock keeps on his tirade about better paths they could have taken. It makes it slightly more difficult in the dark, he mentions, because it's easier to lose someone then, for the eye to trick you and your sight to betray you.

Against the wall completely, John sinks down. "Sherlock," he says, his voice unnaturally thick and low.

Sherlock's sight is one that comes clearly, in full force, at dark liquid dripping between John's fingers against his torso. He's frozen for more than a split second this time. Three seconds. Five seconds. Eight seconds, and then he trips over a broken piece of plywood sitting in a puddle of dirty rainwater to fall on his knees with the burning desire to scream until his lungs burst into red-hot flames.

Instead of comforting words, all he can say is, "You said it was just a nick." He puts his hands on either side of John's face and stares at him with anger and fear and compassion he didn't know he knew how to feel. His body betrays him regularly around John.

"May have not been so honest, sorry," John slurs, the joke in his voice but without a smile on his face.

Sherlock's brain almost shuts down before he remembers his phone. He texts, because he's faster this way.

ALLEY BEHIND THE BOOKSTORE, JOHN STABBED. HELP NOW. SH

Lestrade knows where they are and God help him if he doesn't come within the next 60 seconds.

John's eyes slip closed, his head leaning back, and Sherlock screams, "DON'T YOU DARE!", which causes John to open them back up and wince.

"Yes, no, I wasn't."

Still Sherlock's mind and body are a flurry of emotions he thought had been stored away only for analysis, not personal use, which is a far less important thing to think about than John bleeding on his coat, but still horrifying, nonetheless.

Oh, God, he thinks, if he doesn't live.

They are inches apart, and Sherlock whispers, "Please." John opens his eyes again, a fierce, determined stare back at Sherlock, light still in them.

Then there are hands on his shoulders and voices in the background that Sherlock would normally listen to, remembering every detail of everything they say, but he shuts down, drowns out, using every ounce of energy to will John to stay alive simply by looking at him.

John continues to look back, refusing to let his very tired eyes blink, and Sherlock's heart beats faster because he's afraid and triumphant and thankful all at once at what John says without ever uttering a word.

"I won't leave you."