"Funeral?" John asks. Is that what this is? "Not my own," the Doctor jokes. "Not yet." John Smith inspects him. "I'm not as young as I was. Well, not as young as you were when you were me..." The Doctor's confused. He really doesn't remember John, at all. Everything he did, lost to thankless memory. "But you're the Doctor! The next Doctor..." John's eyes devour the Doctor, his entire body, everything about him. Trying it on, with his eyes; thinking of his son across the Void. "Or the Next-But-One...? A future Doctor anyway." He considers spoilers, asking how it happened, and rejects them aloud. "Although... I hope I don't just trip over a brick, that'd be embarrassing. Then again, painless. Worse ways to go, depends on the brick..." It will. Everything will.
"You're gabbling, sir," the Doctor notifies him, not unkindly. "Now, might I ask, who are you exactly?" John Smith realizes he's fucking up, spoilers from the other side, and shuts his mouth before opening it right up again. "No, I'm, uh... I'm just Smith, John Smith. But I've heard all about you, Doctor. Bit of a legend, if I say so myself." The Doctor is wonderful, adorable, with his chest puffed out: "Modesty forbids me to agree with you, sir... But yes. Yes, I am."
"A legend with certain memories missing, am I right?" The Doctor is surprised; the way John Smith's eyes pin him to the wall. "You've forgotten me," he says. The thing they can't afford to forget, lest they repeat their old mistakes. "Great swathes of my life have been stolen away," the Doctor agrees, sadly. "When I turn my mind to the past, there's nothing." Going back to the Cybermen's appearance, in fact, precisely. "Masters of that hellish wall-scuttler and old enemies of mine, now at work in London Town. You won't believe this, Mr. Smith, but they are creatures from another world." His language is comforting, virile and sure; John is sweetly patronizing: "Really? Wow..." The Doctor is proud, of his secret world, and continues excitedly. "It's said they fell onto London out of the sky, in a blaze of light. And they found me," the Doctor relates, looking into a street fire and seeing something there, something terrible and unreachable. "Something was taken. And something was lost."
"What was I like?" he suddenly asks, turning himself from the memory. "In the past?" He stares into John's eyes, searching for clues that won't get him too close. "I don't think I should say. Sorry. Got to be careful with memory loss. One wrong word..." John Smith walks heartless through the snows of London Town: left one across the Void, the other in Chiswick. This Doctor is more like her than any of them know, yet. One wrong word... She's with him all the time.