He was woken up in the middle of a rather nice dream by Diana shaking his shoulder. “Wake up,” she said. “Charlie’s given us fifteen minutes to have some breakfast and get packed up before we leave.”

     “Aaargh!” complained the wizard, rubbing his eyes. “That monster’s a slave driver...”

     He stopped abruptly when he realised what he was saying. Slavers were indeed slave drivers, subjecting vast numbers of slaves of all species, including humans, to a life of unbearable suffering and misery in their deep underground cities before killing them by literally sucking their organs out. He blushed in shame. “I’m sorry,” he muttered. “Every so often, I find myself thinking of it as a person, as though it were a human being, like us.”

     “Me too,” replied Diana softly. “If only it thought of us as people.”

     “Not much chance of that,” said Thomas, climbing out of his sleeping blankets and looking around to make sure it wasn’t within earshot. “We’re just animals to it, to be slaughtered or put to work. This one seems nice enough at times, but if it wasn’t for the threat of the Shadowarmies...”

     He broke off as the slaver re-entered the cave, followed by Jerry, Lirenna and the trogs, all yawning and stretching, still tired after such a short rest. The creature looked at him, its proboscis pulsing and throbbing as it coiled and uncoiled, and Thomas remembered with a shock that it was almost deaf, that it ‘heard’ what other people were saying by means of its highly developed telepathic senses. Did it hear what I was saying? he wondered fearfully, and if so, how would it be likely to take it?

     To his relief, though, it simply turned away from him and went over to examine the passage leading from the cave. Either it didn’t hear me, he thought, or it didn’t find anything I said particularly insulting which, considering its nature, it probably wouldn’t. He resolved to be much more careful in future, though. Another mistake like that could get not just him, but all of them killed.

     They hurriedly ate a light breakfast, packed away their sleeping blankets and prepared to leave. Jerry, having the smallest blankets, had them packed away first and then tried another bit of illusion art while waiting for the others to finish. He had improved considerably on his first attempt, and was now able to control up to a dozen simple geometric shapes at once. The others watched in fascination at first, but then remembered the slaver and returned to their packing.

     “I wonder if we could take a few of these with us?” said Matthew, holding a crystal bug in his hand and watching as it slowly waved its legs, still trying to walk as though it were on the ground. “If Charl... the ambassador says its light is very dim to him, then it would make an ideal light source for us. Bright enough for us to see by without hurting the ambassador’s eyes.”

     “No,” said the slaver. “Without the minerals in the rocks on which it feeds, it would starve to death in only a few hours, and these minerals are only to be found locally in this cave. That is why they have not colonised the entire World Below.”

     “Oh well, it was just a thought,” said Matthew, putting the bug back down on the ground.

     “A thought?” said the cthillian sarcastically. “Wonders will never cease. Come now, it is time to go. We have a long way to go before we stop again.”

     It left the cave, and the others followed, Thomas and Diana pausing for a last look at the crystal cave and its strange inhabitants before they left it behind.

     The tunnel they were in now was about the same size as the one they’d followed the day before, but sloped downwards at a much greater angle, varying from one in three to one in one, and even becoming almost vertical in some places, the river roaring down a series of stepped waterfalls up to twenty feet high and soaking them to the skin with spray. It must originally have been a treacherous tunnel for potholers to try to descend, with sharp, jagged outcrops of rock and sheer drops that could only be tackled with the aid of ropes, pitons, spiked boots and a great deal of luck and skill, but someone had carved flights of steps in the worst places, and there was a reasonably flat, ten foot wide path everywhere else so that the questers were able to make their way as easily as though they were merely descending from the top of a tall castle to the basement, as the slaver had promised. Thomas wondered which race of subterranean creatures had done the work and after a moment’s thought decided to ask the cthillian, but the slaver replied that it neither knew nor cared.

     A few hours after leaving the crystal cave the tunnel leveled off a little, with an average downward slope of only one in five or six, and it was joined by several smaller tunnels, each with its own small, fast flowing river. Crossing those rivers would have been tricky and dangerous except that sturdy rope bridges had been built over them, their size suggesting that they’d been built by creatures much smaller than humans, probably about Jerry’s size. There was no sign of the creatures themselves, though, except for one extremely brief glimpse that might have been just Thomas’s imagination. They were descending a flight of steps carved from the living rock, smooth and rounded with age so that they were only safe to use at the edges, when he thought he saw something move out of the corner of his eye. He turned quickly to look, raising his glowbottle, and just for a moment he imagined that the dim, red light was reflected from a pair of huge, large pupilled eyes, very close together and about three feet above the ground. It was gone almost instantly, however, if it had been there at all, and there came a sound like bare feet flapping on bare rock, almost hidden by the roar of rushing water.

     He tapped Angus on the shoulder, and the trog looked around at him. It was warm in the tunnels and both the trogs had removed several layers of the clothing they wore as protection against the cold surface conditions, bundling them up and tying them on top of their backpacks. Thomas remembered hearing that they commonly wore nothing at all in their own underground cities, but Angus and Douglas were still fully covered by a couple of thin layers, except for their hands and faces, in consideration for the sensibilities of their companions.

     Angus’s head was totally hairless, lacking even eyelashes, and his pale skin hung in loose folds across his skull, giving him the appearance of an extremely old human. Thomas had found it rather disconcerting at first, but he was rapidly getting used to it.

     “Have you seen any little people down here, by any chance?” he asked, feeling a little foolish. “About three feet tall with huge eyes?”

     “No,” replied the trog. “Why, have you?”

     “I thought I saw something,” said the wizard, “but it must have been my imagination. If you haven’t seen anything with your infravision, then it’s not likely that I saw anything.”

     “Not necessarily,” replied Angus. “If it were a cold blooded creature then infravision, heat vision, would be no good for seeing it.”

     “Are there many cold blooded creatures down here, then?” asked Thomas curiously.

     “Oh yes, a few. More than there are on the surface. It's warmer down here than on the surface, so cold blooded creatures can compete on equal terms with us warm blooders. Better in fact, because it’s so much harder to see ‘em. That’s why we illuminate our tunnel cities, even though we can see in the dark.”

     “I’d love to see one of your tunnel cities one day,” said the wizard dreamily. “I’ve heard so much about them.”

     “I’ll tell you what,” said the trog. “When we’ve found this priest down in the Underworld and told him to get his arse back up to the surface, we’ll take a different route back up again and go through Za-Kora, where you’ll see a few things to tell the folks back home.”

     Thomas was delighted, and thanked him for the offer. They continued talking for many hours afterwards as they descended into the bowels of the earth, the trog describing the marvels of his own home city far to the west, and the wizard telling of all their adventures during their quests for the Sceptre of Samnos and the Orb of Proofing. They lost themselves in their conversation so much that they were greatly surprised when they came to a flat, level area of about a hundred square yards next to the river where the slaver told them they could make camp for five hours. They had completely lost track of time and had completed a day’s march without realising it.

     The river continued its sharp descent the next day, and it got steadily wider and deeper as more tributaries joined it. The path on which they were walking also grew narrower, shrinking from ten feet to six feet, and then to three, forcing them to walk in single file. In places the path actually dropped below the level of the water, forcing them to walk knee deep in the freezing cold water until their legs went numb and with every step on the slippery stone ground running the risk of their being swept away by the rushing river.

     When they complained of this to each other, though, the slaver told them that they should be grateful for the cooling effect of the water as it would otherwise be almost tropically hot, this far underground. "There are places in the World Below where there is no water," it said with its horrible telepathic voice, "where those of your kind can barely exist. You should enjoy the coolness while you can."

     Thomas was busy trying to think up a suitable reply to this when he heard something that drove all thought of his frozen legs out of his head and made him shiver in a completely different way. It was a low rumble from far ahead of them, barely audible over the roar of the river but bringing them all to a dead stop, staring at each other anxiously. “What was that?” asked Matthew.

     “Rockfall,” replied Douglas, looking up at the ceiling doubtfully. “The river erodes the sides o’ the tunnel, and every so often part o’ the ceiling collapses. It's probably nothing to worry about. Erosion is a very slow process and rockfalls don't happen very often.”

     “Let’s hope so,” said Shaun.

     They reached the place where the rockfall had taken place a few minutes later. Most of the falling rock had fallen into the river where it was lost to sight (Why doesn’t the Darksea fill up with sediment? wondered Thomas. Is it also carried back up to the surface?), but a few small boulders littered the path, and trickles of dust and gravel still fell from the tunnel ceiling. They looked up nervously as they hurried past, and sighed in relief when they were well past the spot.

     More rumbles came from the distance, however, both from ahead and behind them, and they realised that the danger wasn’t past. The two trogs spoke frantically to each other in their own language, and Thomas brought to mind the words of the new shield spell he’d only recently perfected, wondering whether it would do any good against lumps of falling rock and whether he’d have time to cast it if he saw one falling towards him. A boulder three feet wide fell into the river just twenty feet ahead of them, causing a terrific splash and a heavy thump as it hit the river bed.

     Gradually, though, the rockfalls stopped, to their renewed relief, although they remembered that their previous relief had been short lived. “Maybe we shouldn’t go any further,” said Angus, now speaking in common again. “This is obviously an unstable section o’ tunnel. There’s probably a minor fault line around here somewhere, and there may be further rockfalls, maybe more serious ones.”

     “But some o’ the rockfalls came from behind us,” pointed out Douglas, “which means we’re already well within the danger area, so it may be no more dangerous to go on than to go back. Also, I don't believe that rockfalls as bad as the one we just experienced can happen more than once every two or three years. Once all the loose rock in the ceiling has fallen, it takes time for the processes of erosion to loosen any more.”

     “Charlie doesn’t seem very worried,” added Matthew, indicating the slaver still striding along in front of them, seemingly without a care in the world.

     “He may just be reluctant to show fear in front of us ‘inferior beings’,” suggested Jerry. “He can’t afford to lose face in front of us.”

     “No, slavers are too intelligent for that kind of nonsense,” said Thomas. “Too arrogant, too. They think so little of us that they don’t care what we think of them. If he was afraid of something, he’d just run away from it, save his own life no matter what the cost, and to Hell with what we thought. No, if he’s showing no fear, it’s because he doesn’t think that there’s anything for him, at least, to be afraid of.”

     “let’s hope so,” replied Shaun and, with more nervous glances at the ceiling, they continued on.