Tracey's Grandmother was an inventor. She went under the name of George. "After George Elliott. Gran was a bit like that. Always taking the piss. No one would accept a female inventor, so she always called herself George and dressed like a comic book inventor. You Know. Tweed jacket. Plus fours and spats, with a monocle, although her eyes were 20/20. She was even known to wear a false moustache for publicity photos. It was for the benefit of the misogynists that largely make up the inventing community. At least that's what she said. It was Gran's little joke. She liked a joke, did Gran. Though most people usually failed to see the funny side.

"Last month, I finally decided that it was time to clear this room out. It's been 10 years, after all. Of course, I didn't know what half the stuff was. Mostly it was bits of stuff that she put in circuits, or bolts to hold things together. I took the best of it down to the car boot. Most of it I took down the tip."

There was a 'but' coming. And the but clearly involved the large wooden box that stood in the centre of the room, minding its own business in the way that large wooden boxes tend to.

"What is it?" Sam asked.

"It took some digging to find out," Tracey said. "There is nothing about it that gives it away. At first, I thought it was just a wooden box. Admittedly, a large wooden box. A large wooden box with a few buttons and dials in it. But just a wooden box nevertheless, large enough to fit a person in. Possibly two if they are intimate. But no more than that." She handed Sam a book. An A4 notebook. The sort that you would have bought at Staples, when Staples was still a thing. On the front, there was a white sticker. On the white sticker were written in a spidery hand, the words, "The Wooden Box - notes"