You look impressive, Mr. Holmes. Standing there, as dominating as I am, even with a gun in your face; you'd be an animal in bed, I imagine. Though, unfortunately, I'll never find out. At least not first-hand – what a pity; but you know that, don't you? You know that we'll never be what I think would be a killer-combination. So you'll flirt with me, act like I fluster you (because on some level, I think I do, even if it's just fleeting moments between derision). That's fine. I can do that too. I can do just about anything.

Except understand you.

You're powerful and godlike, like a black hole, you're celestial and absorbing. But the moment a man threatens to kill me you've gone blank – you don't much mind but I'm interesting so you don't want to see my brains painting the walls. I don't either, it would ruin the colour scheme, don't you think? And then he threatens John.

I noticed him the moment he came in, as well. Not just you, all sharp edges and brilliant eyes; but John with his underrated sweetness. He's the kind of man that would make women fall in love. He's more dangerous than you. You make women beg, I'll bet. You'd be dominating and unrelenting and they'd just fold over themselves for you. But John Watson makes people fall in love with him. He makes them do anything and everything for them without even trying.

And now that the Americans have threatened John, it's all off the walls, isn't it? Your expression turns almost thunderous – as if hissing you dare threaten what is mine? – and you've got the desperation of a dying man in your eyes. You tell them you don't know something, and you'll willingly admit it to save John's life. But I know you, Sherlock; you'll lie and say it was just because John is still useful.

But you don't admit you don't know something.

They count to three, trying to scare you, and it is working. You tell them to stop. You know the codes. I've told you. And I don't want to see John die. I don't want to see this. Couldn't you have left the photos alone? Just chatted over tea and we'd separate. I don't have to pull you into this. This can be between me and Mycroft and Jim. You and John can leave. Go off and have your merry life.

Until Jim finds you. And believe me, my love, he will. And he will try to burn you. Did he tell you that? That he'll burn you. Burn the heart from your chest. And did you look at John when he said it? No, of course not, you're too skilled to do that. But you thought it. Inside your mind and heart a voice whispered john and you tried to ignore it.

Like I said, I know you, Sherlock.

John doesn't look as scared as he should. Then again, neither do I. But John looks like he's worried. Worried that you've found something you can't crack – and the thought of you not knowing something worries him. Because you'll burn yourself trying to figure it out; Jim won't have to lift a finger. So figure it out, Sherlock! Do it so you won't burn and John won't die and this can end.

Ah, there it goes. There's the realization. My measurements; it's very thoughtful that you knew them. I tell you such, thank you for being observant. And I am flattered. Don't tell me not to be. I know you only knew because it was the only thing you could catalogue and so you did.

I bet if I asked you what John's favourite jumper is you'd know. But that's different, isn't it? You aren't cataloguing John, not observing. You watch him. Knowing his habits is a habit of yours.

You're a clever man, Sherlock. But I've got you on this one. I know how this is going to play out and I'm almost sorry to see it through. You'll remember me, though. And, at the end of this game, I'll be the One That Got Away. I wish I could slot myself into your life. I'll admit it was a desire of mine – to enchant you and have you be mine. Never had anything that was mine before; because I was the toy people passed around. Not the player. The plaything.

But I suppose I'll settle for being The Woman in your life.

Since John seems to be everything else.