I've never done a heist before.

'Done', is that right? Does one 'do' a heist? Or does on 'go on a' heist? Or do you stage a heist, now, I know you can do that, stage one, but that sort of implies that you yourself are not involved. Not that I'm saying you're involved, I mean me. Then again, you all are sitting there, knowing all this, and keeping your mouths shut, aren't you? Accessories, that's called. I imagine none of you have been accessories before. That's alright, I've never been a thief before.

Exciting.

Anyway, there's time yet to work out the grammar of the thing. First, I have to be a scientist again.

Conversation between the Ponds has been getting rather heated re: the relative merits of the sequels to Ocean's Eleven. Even though there's only four of us. I was watching from other side of the console until I realized Jessica was doing the same and pulled her back out of the way. When married couples argue, things can sometimes be thrown. Heavy, dangerous, head-clunking-in things.

That's one of the things I learned this week.

They are, however, interrupted by a loud, sharp ding. They stop, and both look around at me. Unlike Jessica, who walks immediately away. Looking for somewhere to hide, probably. She's heard that noise twice before and it's never ended well for her. That's over, now, though, it's ready this time.

'What's ready?' you cry (some of you in good old Companion Spirit, some of you in utter confusion).

Why, my dear accessories, only my latest and greatest invention. The Ponds follow me, down the old east stairwell that got shuffled and is now in the west, past the cattery, through the aquarium tunnel I've always wanted and never knew was here and into the chronocytology lab.

Don't worry if you've never heard of chronocytology. It's only existed since Tuesday. It is, for future reference, the study of time signatures present in the cellular biology of living organisms. And if you ever want a bit of space at a party, you can tell that that's what you do for living, because everybody stops talking.

In the centre of the lab there is a table, with a two-inch edge on it and half-full of what looks like water and is really an incredibly delicate balance of maintenance chemicals and growth proteins. It's a work of genuine genius in itself, that liquid.

I look up into the blank, expectant faces of the Ponds and decide not to explain that.

Floating in the liquid is a sheet, pale, fleshy pink in colour and looking very much like the layer of fat one might peel off slow-cooked pork. Bit thinner than that. Slightly see-through. Wet and milky with my new miracle fluid.

"Pond, grab an end."

"No."

"Rory, grab an end."

"Amy, grab an end."

"Oh, for God's sake." So finally she does as I asked, reaches tentatively into the liquid and picks it up at the corner.

"That's it. Careful; don't tear it. There aren't enough strawberry laces in the world to buy another one."

Pond isn't listening. Pond has seized right up, holding it at arm's length and as much leg's length as gravity will allow, face puckered like there's some foul smell in the room. Which, to be fair, there is. But it's the stench of genius and I will not have it derided. Yet all Pond has to say for herself is, "Where's this going? Quickly, Doctor, where's this going?"

I sigh and guide her to the wall opposite the table, where the lightbox hangs, and we throw the chronocytological map up like an X-Ray.

You understand, I am not just explaining this process to you, but to future practitioners of my brave new science. Hence the detail and italics and the new scientifical terms. Bear with me, I'm starting something here.

This map, grown from a single time-exposed cell of Jessica's being, is a complete history of all her temporal and transmaterial travels. Now, with eighty-one Time Lords and heaven knows what else under her belt, rich and varied those travels may be. But the one united factor of every single trip before she ended up in my box, was that Owner of hers.

Those are sarcastic italics, not science italics.

What I mean is, the return journey always ended in the same place. The very centre, the core of her temporal history, is the place we've been humorously referring to as Silence HQ. And I can see, physically see, that place now. A little dark cluster, like a tangle of nerves, at the centre of the fatty mass. All her other stops, little ports of call, are specks radiating from that point, but those are unimportant. I take a pair of tweezers and, from that central splodge of dark, I peel a scrap of chronocytological matter while I am explaining to the Ponds what they're seeing.

Rory, in the same instant in which he grasps the concept, groans, physically reels, and braces himself against the wall. Pond jumps to him, holding him up.

"What happened, are you alright?"

"I just imagined what his map would look like."

Fair point. I imagine something between a star map and the vanilla seeds in a good ice cream. Maybe a fading, dispersing splodge, somewhere off centre. Drfiting steadily farther from centre, I suppose.

"My map doesn't matter. This one does."

The cytochronological matter is to be placed under a microscope, where at the correct magnification it will resolve itself into a numerical sequence. Co-ordinates.

Co-ordinates which, as I transcribe them, seem awfully familiar.

"No… No, that can't be right, that can't be wrong."

"Rory, poke him, he's gotten stuck again."

I spin on Pond, and I would probably be very scary if I could take my eyes off those numbers and what they're saying to me, "'Can't be right,' Pond, as in 'not possible'. 'Can't be wrong' as in 'not allowed to be wrong'."

I can't be wrong, so I'm going back to the console, so I can plug in these co-ordinates and the Tardis can be the one who's wrong. I will be unsure until the Tardis has told me to be sure.

The Ponds are right at my heels. They're getting very good as following purposefully, as though they know what's going on and are just as concerned as I am. It's very comforting.

I reach the console, and type nothing.

I stop.

There's an envelope propped on the typewriter. Which I didn't put there. Which, I confirm with a quick glance around, neither Pond nor Mr Pond put there. And the writing is neat, legible and unexpressive, which rules out Jessica. Aside from which I recognize the writing. Just wish I didn't, that's all.

There is a letter in the envelope.

It reads: You're absolutely right about the co-ordinates. Once you get the time right it will all make sense. By the way, well done tricking Mummy and Daddy into thinking you know what you're doing. Don't worry about it, though. All the answers are on your doorstep. Keep this letter.

Across the console from us, there used to be a gun lying on my chair. River left it behind when she stormed off the other day. It's not there anymore.

In utter shock, I can only exhale, "She never leaves, does she? I mean, she just never stays away for any length of time, she's just always here, isn't she?"

"Who is?" Pond asks. She steps up to read over my shoulder and I tuck the letter very quickly away.

"Rory, get the door, would you?"

And it's all very predictable; he begins to ask what on earth I could possibly be talking about, and is cut off by the knock at the door. He then promptly goes to get the door, like he was asked.

They should all just do what I ask them to do the first time. That's where it always ends up anyway. The rest is just defiance and delays, endless delays.

While Rory is between us and the door, Pond steps up, asks me quietly, confidentially, "That letter was from River, wasn't it? What's going on between you two?"
"What ever could you mean, Pond?"

"I mean she knows everything before we've even been there and she's… helping? She's helping, Doctor, isn't she?"

'As opposed to what, Amelia?' That's the question I want to ask her. Those are the word I'm all but ready to put to her. I want to see where she's going with this, just what exactly is going on in her mind right now that would make her say a thing like that. 'Helping' as opposed to what, exactly, does she think River could possibly be up to? Why would River do anything else but help and why would she help if not for the best of reasons, with the best intentions?

Of course, I say nothing.

Nor would I, even if we weren't momentarily distracted.

Rory, you see, opens the Tardis door. Instantaneously declares, "Oh, anybody but you," and throws a punch which both Pond and I not only hear but feel connecting.

So there's that to deal with…