I looked around and realized I had no idea how long we had been walking. I could still see daylight between the trees but this was the time when the sun never set, and I guessed it might already be late. I didn’t like the thought of sleeping in the woods but there didn’t seem to be any choice. There was no sign of habitation; no shelter, not even a woodsman’s hut. We continued along the narrow path, until at last we came to a glade, in which there stood a building. It was a strange and shapeless building; not quite a hall, and not quite a cave; there were no doors or windows; and the opening, whatever it was, seemed almost as broad as the ceiling was high. It was a decent size, though, and although it didn’t look (or smell) too welcoming, it would at least provide shelter.

‘Let’s sleep here tonight,’ I suggested. ‘It looks completely abandoned.’

The children looked at me doubtfully. Perhaps they’d expected their gods to provide better accommodation. But we’d been walking for hours by then, and I was cold and exhausted. The cave – the building, whatever it was – would keep us dry till morning.

And so we slept for an hour or so, until we were awoken by a crash. There followed an ominous rumbling sound, the ground rocked like a boat in a storm . . .

‘An earthquake!’ said Thor.

‘Terrific,’ I said.

Thialfi and Roskva clung to each other. Both were pale and trembling. I made for the cave entrance, half expecting a rock-fall, but almost at once the rumbling died down, and so did the rocking movement. Soon, everything was calm again. If it had been a quake, it was over.

Outside, the rain continued unabated.

We debated leaving the shelter. Another earthquake might trap us inside the mysterious building. On the other hand, a night in the woods was hardly a welcome prospect.

‘I don’t see how outside is going to be any safer than inside,’ said Thor. ‘There may be wolves in those woods, or worse. I say we stay here tonight. Perhaps we can make a stand if something attacks. I’ve heard there are monsters in these parts.’

‘Now he tells me,’ I muttered.

And so we retreated to the back of the hall, where, in the semi-darkness, we found a kind of shallow cave leading off at an angle. It was warmer in there, and more secure; if it came to a fight, at least we’d have the wall at our backs. We slept there, but badly; twice more in the night there were sounds – a muffled bellowing. It might have been Thor breaking wind in his sleep, but on the whole I doubted it.