“Nothing’s happened,” Dunworthy said. “I’m merely pulling her out as a precaution.”

“What do you mean, a precaution? Against what?”

I knew I shouldn’t have let Colin into the lab, Dunworthy thought. “There’s been a slight increase in the amount of slippage,” he said. “And until we know what’s causing it, I’m not sending historians on multi-part drops, that’s all. I was unaware that Polly had left on hers or I would have stopped her from going. Since she’s already there, I’m bringing her back.”

“I’m going with you.”

“Don’t be ridiculous.”

“No, I must,” Colin said earnestly. “I promised her I’d come rescue her if she was in trouble.”

“She is not in trouble—”

“Then why are you pulling her out? And what do you mean, a slight increase? How much?”

“Only a few days.”

“Oh,” Colin said, and Dunworthy could see the relief in his face.

But he was a bright lad; he’d make the connection. Dunworthy needed to get him out of here. “Colin, I need you to go to Props and tell them I need a 1940 identity card,” he said, afraid Colin would balk at leaving, but he was eager to help.

“What name do you want on the card?” he asked.

“There’s no time to make up a special one. Have them give you whatever they have on hand.”

Colin nodded. “You’ll need a ration book, as well, and a shelter assignment card and—”

“No, I’m only going through for a few hours,” he said. “Just long enough to locate Polly and bring her back.”

“But you’ll need money for the tube and things. And what about clothes? Should I go to Wardrobe and—”

I can just imagine what Wardrobe would come up with, Dunworthy thought. “No, I’ll wear what I have on,” he said. A tweed jacket and wool trousers had, thankfully, been wardrobe staples for a century and a half.

“But you’ll need a gas mask. And a steel helmet,” Colin said. “It’s the Blitz—”

“I am fully aware of the Blitz’s dangers,” Dunworthy said. “I have been there several times.”

“Sir?” Badri interrupted. “I think you should send a retrieval team instead of going yourself. It would only take a short time to set one up and a day or two to prep them—”

“There is no need for a retrieval team.”

“Then at least someone who hasn’t been to 1940—”

“You could send me,” Colin said eagerly. “I know all about the Blitz. I helped Polly with her prep—”

“You are not going anywhere,” Dunworthy said, “except to Props to fetch me an identity card.”

“But I know when and where all the raids were, and—”

“Go,” Dunworthy said. “Now.”

“But … yes, sir,” Colin said reluctantly, and ran out.

“How long before Linna will have those coordinates set up?” Dunworthy asked Badri.

“A few minutes. But I really think you should send someone who hasn’t been to 1940 before. You’re clearly worried about the increase in slippage making it impossible to pull people out by their deadlines, which means you shouldn’t—”