“Unit twelve,” Illiun called. “Have you found something?

But the sentinel didn’t respond; instead he was humming to himself, a disconcerting sound that had something of the angry drone of wasps about it.

Drawing closer to the stones around which the silver-eyed man was dancing, Silus could taste an unpleasant sour metallic tang in the air. He looked down to see the hairs on his arms rising.

“Magic?” he asked Kelos.

“No, I don’t think so,” said the mage. “It feels a bit like that first time we stepped aboard Illiun’s ship; that same charge in the air.”

“Shouldn’t somebody offer to be our silver-eyed pal’s dance partner?” Dunsany said. “It looks like he’s getting a bit twitchy.”

The speed with which the sentinel was circling the stones was increasing, each loop drawing him fractionally closer to the rocks until, inevitably, he came crashing to a halt.

The sentinel lay in the sand unmoving, staring up at the boulder with which he had collided.

“What the hells was all that about, Illiun?” Katya said. “Was the thing supposed to do that?”

“Unit twelve, report.” Illiun called.

The sentinel didn’t move.

“Unit twelve, report!”

Dunsany went to stand over the prone figure. The silver was fading from the sentinel’s eyes, flickering slightly as they dimmed. His mouth was stretched into a rictus grin and his fingertips danced lightly over the sand. Dunsany knelt down and put his fingers to the sentinel’s throat but could feel no pulse. He leaned over and put his ear close to the silver-eyed man’s mouth, listening for any sign of breath. But instead of the soft whisper of exhalation, there was a low buzzing sound, slowly gaining in pitch.