I have loved this, Sherlock. The fun little game of ours; the twisted dance that we do around those that are too stupid to see it. Our great game – Jim VS Sherlock; do you wonder who will win? Do you think it's you? Maybe; I can see you thinking that, but you're wrong. Oh don't whine about it, dear. You know why it's you. Why you're going to lose and I'm going to win. You understand it. It's because of your pet. That little thing you keep – I once told you I ought to get a live-in. But there's the difference.

I won't care. If I get one I won't care at all because I don't want to. Also, it'd be boring to care about someone. Restraining yourself so you don't hurt their feelings – how intolerable, but necessary I imagine. Hence why I won't do it; oh, but you have.

You've called your own little pet and you've gotten him a leash. Bought him a shiny new collar and gave him a bed. You feed him and drag him everywhere. You care now. My dear; that's a danger – but what do you care? You tread with angels. I walk in shadows. But, what's that line? Where angels fear to tread – yes, you fear me.

You'll never admit it but you are afraid of what I can do. So you want to stifle me. Or do you? Maybe, oh just maybe, you want me free and out there. So you'll never be bored. I am the only one to elude you after all. To win; and that's why I'll win this battle.

But you don't believe me. That's just the issue, isn't it? You don't believe me. You think you'll win. However, and I've said this before – do try to pay attention to me, Sherlock, I do so crave your attention – you won't win. You're deluded. And I know the problem.

Your pet. Yes, yes it all comes back to him. But I was watching you before, I saw how brilliant you were – like a star. And now you've become domestic. Now you've been infected with your pet's ignorance and the wound is festering. But I know how to help you. Cauterize the wound. Burn it out of you. Burn the heart out of you. You see, Sherlock? This was all to help you. To make sure you will always be as brilliant as you can be. Not as brilliant as I am, mind you.

People die, Sherlock. They wither and bleed and sometimes, if they're very lucky, it's nature's course as opposed to the course of a bullet. But I'm the gun, my dear, and you're my bullet. And I'll trap you in a chamber if it means having you on my side. Because, much like you without me, I'll be oh so bored without you. Or maybe I'll just keep you as a pet. Use you when I like and leave, let you chase after me, never gaining ground. Like a fly you'll be trapped in my web. Ah, yes, I'd forgotten – you don't know nursery rhymes. Pity. Did you ever hear the one about the want of a nail?

No?

Well, it's not important. What is important, Sherlock my dear is to be sure you know what you're doing as you choose John Watson. Because he is a disease, a sickness of the heart and mind; and you've fallen ill.

Let's remedy that, shall we?

Let's throw the match down.

And watch John Watson burn.