The old woman’s pale blue eyes flew wide when she saw what I was carrying. She didn’t tell me off.

“I suppose you’d better lock the door,” she said.

I don’t think Nancy Campbell would have ever allowed us near each other if she’d guessed what collaborators we’d become.

Jane rubbed her hands together. I sat the wooden case and cardboard box on the bed and, remembering Felix Baer and his records, turned on the wireless. It took half a minute to warm up. It felt like the longest thirty seconds of my life, longer than waiting for bombs to explode during the Blitz.

But at last we were in the middle of a lovely swing tune, and I turned up the radio—not too much, as I didn’t want to arouse suspicion, and our operation ought to be a quiet one. I opened the case.

I had thought it was some kind of typewriter when I caught my glimpse of it on the piano. But it wasn’t. There was no place to fit paper. Instead, above the keyboard was a plate of letters that exactly matched the keyboard itself. Above the letter plate were three dials and a switch.

Jane was out of her chair, hanging on to the headboard of the bed so she could get closer. The front flap of the box came unlatched and fell open as she sat. We both saw the brand name printed on the inside: ENIGMA.

Jane bent to read the metal card, all in German, that was screwed into the inside of the top lid.

“It says it is a cipher machine,” she breathed. “It must be for creating code. Or translating code.”

“Are those instructions?” I gasped.

“Not useful instructions,” Jane answered. “Just cleaning instructions! But it tells a bit about the moving parts.…”

She kept reading, and I bent alongside her to get a closer look at the machine.

The last keypad in the bottom right corner of the keyboard was missing.

I took the L key out of my pocket and tried to place it over the empty peg. It didn’t fit, but as I pressed the peg down, a Q suddenly lit up in the letter plate above the keyboard.

“It’s battery-powered,” Jane said. She straightened up and tapped at other keys. Random letters lit in the display plate. Each time they lit, one of the dials moved along a notch. “It’s in perfect working order.”

“The letters don’t match!” I exclaimed.

“It mixes them,” she said. “Then they’re in code. The lid says to refer to instructions we don’t have.”

“Maybe we can figure it out,” I said.

Jane opened the cardboard box. Inside it, wrapped in a flannel cloth, were two notched steel gears each about the size of a tin of shoe polish.