Two days before Christmas, Lucy Cole steps out of the cab and collects her bags. She hesitates a little at the man loitering at the top of the stairs to her building, but he's well-dressed and she's never seen him before, so he's nothing to do with her and she doesn't look at him again.

"Lucy Cole," he says as she takes the first step. Her head snaps up. He's not as old as she'd thought before, not so much older in fact. Indifferent haircut, very good coat, intense eyes. Not about her father or a car-crash, she thinks. The next round of the unending divorce, then.

"If it's about Tom, all that goes through my lawyer." She can't get through without going past him. She's got shopping and was looking forward to kicking these heels off and turning the heat up, and this man is not someone she'll be inviting upstairs. And whoever he is, he isn't wearing a scarf.

"Once upon a time," he starts. "There was a London very much like this one, in a universe just different enough. I met a girl named Lucy Cole there - very much like we're meeting now. In fact exactly. I showed her the end of everything, and we married, and were very happy for - oh, nearly a year."

"That's a strange story." And it should scare her, how matter-of-fact he is, like he's reciting history. And how he's still blocking her way. But it's mid-day and people are passing, and her phone's just in her pocket if she needs it. "And then?"

"We wanted different things. So I died, then came back, she died... Now I'm stuck again, here in your universe. And here you are, Lucy Cole."

"Oh,"she says. "And now you want to do it all over, is that it?"

"No. Now I want you to crash a party with me. Here, Earth, London, tonight."

She tips her head, which gives her an extra second to think it through. Then she sets her bags down so she can cross her arms at him. "We were married and you only want me to help you sneak into a Christmas party? I think I'm insulted."

"You aren't." He walks towards her, down the stairs, closing in. "You should feel frightened of me, and you aren't. You should be cross I've upset your plans, and you aren't that either. No church wedding, no paradox, no end of the world, and not a single press conference. One party, we meet the right people, and I'm gone."

The right people. That is the important thing, her best asset. And she can't decide whether he's a right one to know. Not likely, if he's trying to get away to somewhere where she's dead.

"I don't even know your name." She wonders if she said this before. If Lucy Cole is utterly predictable.

"I wouldn't come here on the off-chance. Call me Harold Saxon."

"So I'm not to know your real name. Are you even human?" She's never liked science fiction and resents having to think about other universes and species, and where the differences might be. He doesn't look alien, he looks practically Government.

"No, no, and not here on the doorstep."

And is he actually reading her mind? He's a step below her now, she finally realizes. The way's clear for a dash, if she wanted to run inside. Or make him catch her. "I am not having you up, Harry Saxon."

"Good. Let's not ruin each other this time. But wear the red."

"You haven't given me one reason to go, except to be somewhere I shouldn't and not be somewhere I should. And I look consumptive in red." But she'd bought it anyway, hadn't she? A splurge for the back of the closet, years ago, before she married.

He smiles, for the first time. "Because not a single person in this universe thinks Lucy Cole is dangerous."

Her jaw drops, not entirely by art. "Dangerous. Me."

"Lucy Saxon assassinated a Prime Minister." As though it's as much fact as his other universe and his resurrection.

"I never!" The hands to her mouth, they're half for show. She's smiling behind them, and thinks she can almost see the shape of his delusion.

"No, but you could. I'll be back at eight, you call the taxi. - Yes, by the way."

"Oh, you can't have been Prime Minister." As though it's a magic trick and not pure madness.

His eyes light, and she thinks suddenly that he might after all be trouble. "That and more. I'm the Master."

"You're wicked, Harry." She bends to scoop up her bags, and he gets the last two and hands them to her. "Eight o'clock."