We kept digging in the warm place, carving small shelters, fortifying the entrance and hollowing out private areas for each family to last the winter in warmth.

The elders would not join us, they refused, the old beliefs would not let them near the cave. They said it was cursed, and we fought with words and anger, they said we would not be allowed back if we stayed the winter there. I swore at my grandfather and told him he would die, alone and hungry in his hut. He spat on the ground at my feet. It was hard, but we left the elders at the village, left them to make their peace with their old dead gods.

Those who came with us from the village were stronger, the lack of food during our long hunt for the cave must have weakened us, for even the womenfolk were capable of faster digging than the hunting party. Our newcomers brought the last of the village’s food with them, the winter stores of dried venison and hard bread.

The renewed vigour of our reunited tribe and food fuelled our redoubled efforts, and we were rewarded when Pareev hit a hard thing that rang like metal when struck with shovels. We moved diggers from the other teams, who were busy carving out living areas. We dug rapidly around the metal, making swift progress. It was hotter here, easier to dig without frozen hands and feet. Over a few days the enormity of the thing was revealed.

Pareev was dead the next week, his hollow visage haunted my dreams.

But his discovery: a massive metal dome, smoother than our finest blacksmith could hammer or cast. The dome’s godly perfection marked repeatedly around every side with the same patterns as the shrines surrounding the cave. This must be the source of heat, of otherworldly power. What marvels the ancients had wrought!

There had to be a way in, to the centre of this blessing of warmth, but, no matter how much we dug, we could not uncover an entrance, it was sealed from all sides.