subtle vibration ran up his limbs, into his chest, making his hairs stand on end. He crawled forwards. The vibrations increased. He crawled a bit further, and they receded. Left? No. Right? Yes, the vibrations increased further. He crawled forwards again. It was slow, painstaking progress, but gradually he homed in on the floor slabs producing the greatest vibrations. It was here, somewhere – though he still wasn't sure what he was looking for. He was dimly aware that Charlie and Natalie were staring at him, but he blanked them out. Ben's eyes locked on the slabs – some were no bigger than a brick; others could have held a car. They were solid, unmoving, built by a master craftsman many centuries ago.
Ben wasn't sure how he spotted it, but he knew when his eyes ran over a small, perfectly square slab that this one was special. He put his hand on the centre of it, and gently pressed down.
There was a loud click, followed by the rumble of cogs moving.
Natalie screamed.
A giant slab was moving, creating a large black hole in the ground. Natalie was on that slab. She leapt to safety, landing next to a stunned Charlie.
Ben got up and hurried over to the hole, and the three of them peered into it. Blackness, total and complete. Natalie pointed her spellshooter into the hole, but the light was too weak to penetrate.
“You did it,” Charlie said. “Now, any volunteers to jump into the black, bottomless pit?”
“I'll do it,” Ben said.
“What a surprise.”
“Be careful, Ben,” Natalie said. “You have absolutely no idea how far the drop is.”
Ben was very aware of that. Just looking into the blackness made his stomach do unpleasant things.
“This is obviously a way in,” Ben said, trying to convince himself as much as anyone. “I can't see how they would make a drop that would kill someone.”
Ben sat down so that his legs were dangling over the edge. It really was black down there; he felt like he was jumping into space. Several times he tried dropping down, but his body's natural desire to survive kept holding him back.
“Do you want me to push you?” Charlie asked, with a perfectly straight face.
“No, I'm fine.”
Ben counted down in his head. Five. Four. Three. Two. One.
With a cry, he leapt off the edge, into the black hole. He extended his arms and bent his legs. The fall seemed to take forever, but it was only seconds before Ben saw the ground rise to meet him. He landed painfully and rolled, his knees absorbing most of the fall. The rock was hard beneath his body, scratching and bruising his exposed skin. He lay there for a moment, heart hammering, until his ragged breathing slowed. Then he stood up and dusted himself down. The fall had been less than ten feet. He could see the faces of Charlie and Natalie peering down, but from their anxious faces it was clear they couldn't see him.
“I'm fine!” he shouted up to them. Their expressions didn't alter; so they couldn't hear him either. Ben cursed. He would have to be quick, in order not to worry them. He appeared to be on some sort of ledge. There was a dim light that permeated the place, though Ben couldn't identify its source. Ben walked tentatively to the edge. The sight that greeted him took his breath away. It was a cavern so vast that it looked like an underground mountain range. Cliffs, rocks and caves descended as far as the eye could see. There were small plateaus at various points, providing brief breaks for anyone trying to climb down. Ben loved climbing. He used to seek out the biggest trees he could find and even belonged to a rock climbing club. But this was something else; this was a hundred times bigger than anything he'd ever encountered.
A sudden thump and a curse broke Ben's hypnotic gaze. He turned and saw Charlie lying flat on his back.
“Oh, that hurt!” he said, sitting up and rubbing his backside.
“What are you doing down here?” Ben asked, with surprise.
Charlie gave him an angry look. “I didn't have a choice, did I? You vanished, and you weren't responding to our calls. We had no idea what had happened to you.”
Ben felt a sudden rush of gratitude towards Charlie, knowing just how dangerous that jump was. For all he knew, Ben had jumped to his death, and yet Charlie had still followed him.
“I'm sorry,” Ben said. “I could hear