Although they were both large island countries, few people travelled from Salay to Dearth other than for business. There was the regular air route linking them, as well as a long sea crossing, notoriously prone to stormy weather. Not many islands lay between us: the Dream Archipelago in the southern hemisphere had many clusters of inhabited islands, but only a handful were in the deep, rough seas a long way to the south of Salay. There was a sense of emptiness and oceanic vastness between the two countries.

When Jo or I travelled we normally headed east or west, or sometimes northwards into the marvellous, sun-baked islands in the horse latitudes of the Midway Sea. Dearth had never attracted us. Apart from business executives and office workers, those who did travel to Dearth were mostly backpackers, bird watchers, rock climbers, loners, extreme sports enthusiasts, modern questors or adventurers, drawn by the wild, rugged and so far unspoiled terrain along the east coast of the island.

I remembered the plane I arrived on had flown low for several minutes above this sort of landscape. The pilot came on the PA and said that because of the weather over the sea we had lost more than an hour of flying time, but that Dearth was known for its gravitational anomalies and that we could take advantage of one of them. He advised us that we need not reset our wristwatches.

I hadn’t the least idea what he was talking about: he delivered the message in the bland, supposedly reassuring voice that flight crew often use when speaking to passengers. Whatever he meant, it turned out that when the plane finally landed in Tristcontenta Hub, we were in fact about ten minutes ahead of the scheduled arrival time. I had no idea how that could have happened, but once I was inside the terminal I noticed that my wristwatch showed the same time as the clocks.

What did a gravitational anomaly look like, and how had the pilot found it? I had no background in science, certainly not physics. I fancifully imagined there must be a metal grid or a dome out there, or a series of masts with lights on. But there was nothing in the darkness. It could be anywhere. I was bored.

For a while I read one of the ebooks I had saved to my laptop, then I glanced through my speech again. I made a couple of small changes, improvements. I listened to music on my headphones, then because they isolated the sound I took them off. The train was moving faster now but there was still no sense of urgency. Marooned in my pod compartment, the only sounds I heard were the noises from the wheels and the track and it still seemed to me that I was alone on the train.