It's an old woman who meets Martha on the docks in New York. She's standing there, bold as brass, with her long white hair streaming in the wind and her arms crossed.

"Well, come on then," she says, with an accent that sounds a bit Scottish. "You're the woman who's traveling the world. You should come with me. I can keep you safe."

Martha adjusts her pack on her back and follows. "I'm Martha Jones," she offers.

The old woman nods, and picks up a cane. "I'm Amelia Williams. You can call me Pond, if you like."

Martha smiles uneasily. "Aren't you afraid of the Toclafane?" she asks. She's spent months hiding, keeping to the shadows. Watching other people get killed while she stays hidden. "They won't notice me, but you aren't safe."

Pond snorts. "I'm safe," she says. "The Toclafane wouldn't dare touch me."

And somehow, amazingly, it seems to be true. They walk for more than an hour, and while they see Toclafane, they never come close. And then, they cross a line, and it's like they're in a different city. There are no broken windows. The lights are on in the brick buildings, and the hedges are trimmed. "Welcome to my home," Pond says. "The Toclafane don't come here."

Martha stares. "How?" she asks. "How did you do this?"

Pond shrugs. "It wasn't me. But we're a bit of a special situation here. I think- and this is just a theory mind you- that the Toclafane are time travellers. And this place is locked away from time travel. They avoid it."

It's a mad thing to say. But it's probably right, so Martha doesn't ask questions.

The buildings are packed with people- mostly children, Martha realizes. Pond taps her cane on the rainpipe as she walks into the building. "We have a visitor!" she calls. "All up, and mind your manners!"

The children line the walls, wide-eyed but neat in carefully patched clothing. "I can't save the entire city," Pond says, fiercely. "But I can damn well try to save the children. Come along, Martha Jones. It's supper time."

Dinner is a mad affair, served on picnic tables on the grass in between the buildings. Martha ends up sandwiched between two little girls who don't talk, but stroke her hair if she lets them. A dark-haired woman sits down across from her, and holds out a hand to shake. "It's a pleasure to have you here," she says. "I'm Michelle."

"Martha Jones," Martha says, automatically, though Michelle almost certainly knows that.

"Welcome to the madhouse," Michelle says, smiling. "But it's safe, at least."

"D'you know why?" Martha asks. "I've been nearly the whole way around the world, and never seen anything like it."

Michelle shrugs. "I don't know," she says. "But Amelia says it's safe, and so far she's right. The Toclafane don't bother us at all. We mostly have problems from other people."

Martha can understand why. She's seen plenty of that, too. There are people out there hurting, starving, who would kill for the chance to sit at this table. "You must have some protection there, too."

"It's all Amelia," Michelle says, nodding. "She went and made deals with the gangs around here, the ones that were left, and the ones that came later. Any of their kids who survived the Decimation, they came here. And in exchange, they look out for us. Bring us food shipments and so on. We do garden, too. The kids help out. We all work together."

"What about you?" Martha asks.

Michelle smiles, a little sad. "My kids died in the Decimation. Amelia lets me help."

After dinner, Martha gets up and tells her story, tells them all about the Doctor. "And I know," she says. "I know him. I've loved him. And he will save us."

Afterwards, after the children are shuffling off towards their beds, Pond comes to her. "I thought that might be who you were, Martha Jones," she says.

Martha looks at her, unsure what she means.

Pond sniffs. "You're right to have faith in him," she says. "But you're right to have faith in yourself, too. He will save us if he can, that Raggedy Man. But sometimes, he needs help."

Martha laughs, and tears spring up in her eyes. "Yeah, he does," she says.

Pond nods, as though something's been decided. "We'll see you off in the morning," she says. "Sleep well."