‘Ye gods,’ Swallow murmured soon after, shaking me and pointing ahead. ‘Look.’

I realised that I had been dozing for I was slumped back against his chest and one of his arms was wrapped around my waist. I sat up, embarrassed, remembering the kiss he had once stolen, but then I saw what he was pointing to and my skin grew cold, for the ground ahead gave off a halo of the distinctive greenish-yellow glow of badly tainted matter. Worst of all, we seemed to be making for a slight rise beyond which the glow was brightest.

‘Ask the wolf if we must go where the taint is worst,’ I sent to Darga.

‘The graag do be ahead,’ Rheagor beastspoke his answer directly, distantly.

‘I can see that for myself,’ I muttered, but the wolf had gone from my mind.

Within an hour the lead wolves had reached the bottom of the long slope that we had been moving towards, and were flowing up it. It looked black to my eyes, with the glow of taint shining up behind it, and it was clear that we were making directly for the leading edge of the glowing terrain, for the ground either side of the slope did not glow for a good way further on. Why would we enter the nearest tainted ground? I knew well that any ground that glowed like this was virulently poisonous. So far as I could see there were no darker places in the halo of light to suggest there were less tainted patches. Was it possible I had mistaken the wolves and Rheagor had meant only that he would lead us to the graag by the least tainted route they could find?

The wolves poured up the slope and vanished, but when Gahltha reached the top, I did not see them racing down the slope as I had anticipated. The hill was cut off by a blunt cliff that dropped away, as if someone had cut a wide slice from the centre of the hill leaving a gap, where they had then dug a deep wide hollow that had filled with water.

Only the Beforetimers could or would do such a queer and incomprehensible thing, I thought, and indeed twice in the mountains the broken roads had passed through smaller hills from which a similar cut had been taken to allow the road to lie flat, instead of simply going over it. I saw now that the brightness I had taken for the leading edge of the tainted ground ahead was actually coming from the water.

The wolves were streaming down the side of the hill to curve towards the pool. It was only as we followed that I noticed the end of an enormous Beforetime pipe protruding into the water from the flat face of the hill opposite. I thought at once of the huge pipe that had been crushed under a rock fall behind the observatory.

‘I am guessing the wolves knew this was here?’ Swallow murmured.