One of the largest rides was called the Scrambler: mobile cars, circulating on metal tracks, were spun by the turning of the main platform, moving speedily across several gradients. Next to this was a square building, painted red all over. The lintel carried cursive lettering painted in gold: Willer’s World of Wonder and Magical Memories! There were three steps up from the ground, a narrow walkway and a solid door.

‘We have retained as much as possible of Willer’s original scheme,’ Ketty said, as we paused beside the door. ‘He operated it as a theatre while he was still alive. Inside he had a small auditorium with three rows of seats, and a stage with lights and curtains. We removed the stage so visitors can walk around and look at the exhibits, but the seats are still there. In the season we often arrange with magicians on the island to come here to put on magic shows.’ She banged her fist against the door. ‘This is Willer’s famous unopenable door.’

There was no handle.

Spoder reached past me, and pushed a hand against it. It did not shift. I pushed too, but it seemed pointless to try. It was jammed tight.

‘This door is the only way in and out of the building,’ Ketty said. ‘There are no other exits at all, not even secret ones. It can’t be opened from either side.’ Then she said, without having seemed to move, or have touched anything: ‘The door is now openable.’

It swung freely with a fingertips touch. From the darkness within a long gust of moist air was expelled. It felt hot and humid, even as we stood in the sunlight. The door swung slowly back to the closed position.

‘I’ll put the ventilators on,’ Ketty said. ‘There are no windows.’

She threw a switch on the wall beside the door.

I tried the door again with my hand. It opened smoothly. Lights were now on inside the building. Fans could be heard.