‘He fell,’ Gar said.

‘What? No.’ Hamil gasped. He took a long look at Gar and hugged him again. ‘This world will not be the same without him.’

‘No, it won’t,’ Gar whispered.

Meical was waiting patiently on the slope behind. ‘There are many weary people down here,’ he said.

‘Of course, of course,’ Hamil said, and then they were all moving, Hamil taking Shield’s reins from him and allowing Corban to move deeper into the hall. People began to file out of the tunnel, an exodus squinting and blinking in the light. Buddai bounded over to Storm and they ran off together. Now that Corban’s eyes had adjusted he took a moment to look around, and saw a huge chamber, bigger even than the hall in Murias where the cauldron had been kept.

It was roughly circular in design, the flagstoned floor that Corban was standing upon sunk deep into the ground, broad pillars of light slanting down into the chamber through vellum-covered windows. Wide stone steps led up to great doors of oak and iron. The steps would have stretched the length of the keep at Dun Carreg, so wide that they looked more like the tiered seats of a theatre or a gallery. But all of that was not what took Corban’s breath away. High above, branches as thick as tree trunks in the Darkwood wound their way through the chamber, many of them breaking through the roof, or, as Corban looked closer, perhaps the roof was built around them, as there seemed to be some kind of design at work. A gentle breeze set branches and leaves rustling, as if a hidden host were whispering in the shadows up above them. He turned a half-circle, trying to take it all in, then froze, his jaw opening. At first Corban did not understand what he was seeing so he walked closer. Then he understood. At the centre of the chamber was a huge trunk, wider than Dun Kellen’s keep, rising up and up, disappearing into the shadows of the high roof. The chamber he was standing in was built around the trunk, an outer ring of stone around one of timber, sap and bark.

Something was built into it, at its base, where the stone floor met the trunk.

Corban ran a hand along the bark. It was hard as iron, though not as cold. In fact, there was a sense of warmth, a tingle in Corban’s fingertips. He walked slowly along the trunk, marvelling at it, then reached the construct he had seen.