It was the kind of darkness which causes sheep to leap fences and dogs to skulk in kennels.

Yet the wind was warm, and not so much strong as loud – it howled around the forests and wailed in chimneys.

On nights like this, normal people would pull the covers over their head, sensing that there were times when the world belonged to something else. In the morning it would be human again; there would be fallen branches, a few tiles off the roof, but human. For now . . . better to snuggle down. .

But there was one man awake.

Jason Ogg, master blacksmith and farrier, pumped the bellows of his forge once or twice for the look of the thing, and sat down on his anvil again. It was always warm in the forge, even with the wind whistling around the eaves.

"He could shoe anything, could Jason Ogg. They'd brought him an ant once, for a joke, and he'd sat up all night with a magnifying glass and an anvil made out of the head of a pin. The ant was still around, somewhere-some-times he could hear it clatter across the floor.

But tonight. . . well, tonight, in some way, he was going to pay the rent. Of course, he owned the forge. It had been passed down for generations. But there was more to a forge than bricks and mortar and iron. He couldn't put a name to it, but it was there. It was the difference between being a master farrier and just someone who bent iron in complicated ways for a living. And it had something to do with iron. And something to do with being allowed to be very good at his job. Some kind of rent.

One day his dad had taken him aside and explained what he had to do, on nights like this.

There'd be times, he said, there'd be times – and he'd know when they were without being told – there'd be times when someone would come with a horse to shoe. Make them welcome. Shoe the horse. Don't let your mind wander. And try not to think about anything except horseshoes.