Utgard-Loki gave a smile. ‘That’s right. I was Skrymir. I saw you coming from afar, and wanted to find out who you were, and what kind of threat you might pose to us. Remember the pack with the food inside? I fastened it with the rune Naudr, the Binder, so you couldn’t open it. And later, when Thor tried to smash in my skull with that pretty hammer of his – nice weapon, by the way, but it’s what you do with it that counts – he may have thought he was striking me, but in fact he was aiming for that ridge – the one with the three square-shaped valleys. The valleys are Thor’s hammer-blows.’

Thor isn’t what you might call especially quick on the uptake. He pondered the giant’s words for a while, then frowned and said: ‘And after that?’

‘My man Logi, who beat Loki in the eating contest.’ Utgard-Loki winked at me. ‘That was Wildfire in his elemental Aspect, which is why he looked familiar – and why he ate the trencher as well as the food inside it. And Thialfi, who raced so fast that I could hardly believe his speed, was racing against Hugi, the speed of Thought. And as for you, Asa-Thor . . .’ He turned once again to Thor, whose face was slowly turning red. ‘The drinking-horn from which you took such great draughts – that was a funnel that led to the One Sea, and you’ll see for yourselves when you return how far back the tide has receded. The cat was the World Serpent, that circles the Worlds with its tail in its mouth, and you lifted it so high into the air that you almost dragged it out of the ocean. And as for my old nurse, Ellie . . .’ Utgard-Loki shook his head. ‘That was an Aspect of Old Age, and she only wrestled you to one knee.’ He paused and looked at us all in turn.

‘That’s why,’ he said, ‘this is goodbye. You’ll never see me or my city again. My glamours will hide us for ever. Your people might search a thousand years and still you’d never find us. Let’s chalk this up to experience, shall we? Live and let live, that’s what I say.’

At this, Thor’s face went purple. He grabbed Mjølnir and raised it. But before he could use it, the Trickster of Utgard shifted Aspect and disappeared, leaving nothing but a faint scent of burning and a signature that led deep into the earth. And turning back towards Utgard, we saw that where the gleaming city had stood – its walls, its gates, its shining spires – there was nothing but grasslands and plain, unmarked as far as the eye could see.

‘Wow,’ said Thialfi. ‘Just – wow. Wait till I tell the people at home about this.’

I looked at him. ‘If I were you, I’d keep that story to myself.’

Thor growled: ‘This isn’t over.’