‘What have you got?’ I said, and smiled.

It took the Tunnel Folk some time to prepare themselves for the task I’d set. I explained about Sif’s hair – omitting the reason for its loss – and the smiths all laughed in their sour way.

‘Is that all?’ said Dvalin. ‘Any child could make that for you. It isn’t a proper challenge.’

‘I also want two special gifts,’ I said. ‘One for my brother Odin, leader of the Aesir, and one for Frey, leader of the Vanir.’

This was a political move on my part; Frey, the Reaper, was in fact only one of the Vanir leaders, but he was influential. In favouring him – over Heimdall, for instance – I would be giving him the edge over his friends. With luck, he would remember that when it came to rewarding me; besides, he was Freyja’s brother, and I needed to get her back on my side.

Dvalin nodded and set to work. His brothers and he worked as a team, smoothly and gracefully. One handled the materials; one cast the runes; one tended the forge. One hammered out the hot metal; one finished the piece with a polishing cloth.

The first of the gifts was for Odin; a spear. It was a lovely piece of work, straight and light and beautiful, carved down the shaft with a ladder of runes. It was a regal weapon, and I grinned inside as I pictured the Old Man’s surprise and pleasure as he received it.

‘This is Gugnir,’ said Dvalin. ‘She always flies true, and never fails to hit her mark in battle. She’ll make your brother invincible, as long as he keeps her by his side.’

The second gift looked like a toy; a little ship, so dainty that it made you wonder how Dvalin, with his big, clumsy hands, was able to handle it with such ease. But when it was finished, he said with pride:

‘This is Skidbladnir, greatest of ships. Winds will always favour her. She will never be lost at sea. And when the journey’s done, she can be folded up so small that she’ll fit into your pocket.’ And then he uttered a cantrip, and the ship folded up like paper, fold after fold after fold, until it became a silver compass that he dropped into my hand.

‘Nice,’ I said. I knew Njörd’s son would appreciate this gift most of all. ‘And now for Sif’s hair, if you don’t mind.’

At this the sons of Ivaldi brought out a shapeless piece of gold, and while one of them held it in the forge’s heat, another used a wheel to spin it into the finest thread. Another cast runes; another sang, in a voice as sweet as a nightingale’s, cantrips and spells to bring it to life. Finally, it was finished; gleaming and jewelled and fine as spun silk.

‘But will it grow?’ I asked Dvalin.