They stopped at every room they came to and looked image, finding very much the same kinds of things that Matthew had seen during his first foray. Some of the rooms appeared to be conference rooms, with dusty and brittle centuries old chairs arranged around large tables and with cabinets and cupboards in the corners and against the walls. Others appeared to have been workplaces, or perhaps classrooms, with rows of desks and small tables, each with its own chair. Still others seemed to be storerooms, piled high with crates and boxes whose contents had long since perished and decayed out of all recognition.

One room, smaller than most of the others, was empty except for dozens of cabinets fixed to the walls, each one identical to the one in which Matthew had found the diamond necklaces and made from the same almost indestructible magically hardened wood. Some of them opened, and each one contained several identical items. A dozen silver bracelets. Twenty emerald brooches. Half a dozen pairs of leather boots. Most of the cabinets were still locked tight, though; the locking spells apparently still as strong as the day they'd been cast.

"Why would they lock these away so securely?" wondered Shaun, looking closely at one of the silver bracelets. "It doesn't look particularly valuable."

"Maybe it's an antique," suggested Diana. "And if it was an antique back then, just think what it might be worth today!"

"More likely it's magical," said Jerry. "Let's see."

He cast a reveal spell, and soon the ornaments were glowing brightly as the magical fields surrounding them were made visible. The wooden cabinets also glowed as the spells making them unnaturally hard were also made visible, and those that were still locked had electric bright straps of light across them, some brighter than others indicating those that had passed the test of time better than the others. Most surprising, though, was that the entire volume of the room was filled by a faint luminescence, and when Thomas looked out into the corridor, he saw that it extended all the way to the edge of the magic spell's area of effect, probably indicating that the magical field it represented filled and surrounded the entire complex.

"That must be the spell that creates the gravity," said Lirenna, staring at it in fascination. "It seems to have some kind of structure. Look."

The other wizards looked more closely at the luminosity and saw that she was right. It seemed to be composed of almost invisibly fine strands of light running vertically from floor to ceiling along which rainbow colours were flowing downwards. It was almost as if gravity itself had been made visible, and they all stared at it in adoration until the spell expired and it all vanished, leaving the room looking drab and empty.

"That was amazing!" said Diana, her eyes glowing with delight. "And to think that it's all around us all the time, even though we can't see it any more. The clerics of Tizar say that there's another world all around us that we lack the senses to see, a world of incomparable beauty, and now I know they're right."

"They say that old and powerful wizards gradually gain the ability to see magical fields all the time," said Lirenna, equally entranced. "I can hardly wait."

Matthew, however, was thinking of the magical items they'd found in the cabinets and wondering whether the necklace hidden in his pocket was also magical. "What about these?" he asked, indicating the bracelet Shaun was still holding. "What do you think they do?"

"No way of telling," replied Thomas, taking another and looking at it. "However, items of jewelry are almost always used to carry defensive or protective spells. There are exceptions, of course, as there are exceptions to everything."

"Perhaps we ought to take a few of them with us," suggested Jerry, "in case we come across whatever is it they're meant to protect us from."

"Good idea," agreed Shaun. He began handing out bracelets and brooches, one of each to each of his companions. As he did so Matthew began to feel incredibly guilty as he thought about the necklace in his pocket, and wondered whether it was too late to tell them about it. By keeping it secret, he was denying the others whatever protection it afforded when there were enough in the cabinet for them all to have one. If he spoke out now, though, they'd know he'd intended to keep it for himself, and he couldn't bear the thought of the accusing looks they'd give him when they found out the truth. At the moment, he stood high in their estimation after his success in picking the lock of the door upstairs, something none of the others could have done, and it gave him a warm feeling inside to know that he'd proved himself the equal of any of them. If his greed in trying to keep the necklace secret became known to the others, though, their high estimation of him would vanish and he'd be right back where he'd started. He couldn't bear the thought of that, and he resolved to avoid it at any cost.

He agonised over the dilemma as they left the room and continued down the corridor, and eventually he devised a plan that would, he hoped, get him out of this mess. He would guide them surreptitiously back towards the room where he'd found the necklaces and 'discover' them again, taking the opportunity to smuggle the necklace in his pocket into his hand so that he could pretend to have just picked it up. They'd all take one, in case they did indeed carry defensive spells as Jerry had suggested, and no-one would ever know that he'd had one all along. Matthew brightened immediately. It would work, he knew it would. His reputation was safe.

They hadn't gone much further when they saw, ahead of them, a set of three steel doors side by side in a wall that blocked the corridor, exactly the same as the ones in the other corridor that Matthew had described. Thomas and Lirenna ignored the remaining ordinary doors in the corridor and went straight up to the steel doors, examining them curiously. Remembering Matthew's description of the other doors, they looked at their windows to make sure none of them had red flags in them, and then pulled one of them open.

"Hey!" called out Shaun from behind. "Don't go running off ahead! Wait until we've checked the rest of these rooms."

The two wizards did so, even though they knew there was almost no chance of their discovering the key by themselves, and they kicked their heels impatiently while the others looked through one door after another with agonising slowness. Eventually, though, they were all gathered together in front of the steel door and, with a sigh of relief, Thomas led the way through.

Beyond the door was a small, narrow alcove identical to the one Matthew had described, at the other end of which was another, identical steel door. Going through this they found themselves in a crossroads; a small room with three doors in all four walls, again exactly like the other small room Matthew had described.

"So far," mused Shaun, "apart from the contents of the individual rooms, everything we've seen is the same as you saw in the other corridor. Right, Matt?"

"Right," agreed the younger soldier.

"Hmm," pondered Shaun. "I wonder if that means that this whole complex is symmetrical, like a square? If it is, then those three doors on the right lead to another underground park, whereas those on the left lead to the centre of the complex."

"I say we go to the centre," said Thomas eagerly. "That's where the heart of this place'll be, the place where the whole place was ruled from. If the key's anywhere, it'll be there."

The others agreed, but before they proceeded Shaun looked at the doors heading north and west. They all opened easily, but their twins all had red flags in their windows. "Danger," mused the soldier thoughtfully. "Another reason to go south. Better to explore the safe areas first before we risk facing unknown dangers." So saying, he rejoined the others and led the way through the south doors.

On the other side of the three steel doors and their twins, the corridor ran for about fifty feet with no doors on either side. At the end it opened out into a huge open space, even larger than the ore storage chamber at the base of the spiral staircase, and as they entered their eyes almost popped out of their heads in wonder at what they saw.

The chamber was a hemisphere, at least a hundred yards across at the base and with a vast dome of a ceiling, the highest point of which was fifty yards above the floor. It had no glowing globes of marble in it. The cavern was illuminated by a glowing sphere ten feet across that blazed as brightly as the yellow sun, so brightly that they couldn't bear to look directly at it. It floated above a hemispherical hole in the floor and as Thomas got as close to it as he could, so that he was teetering on the edge of the hole, he could feel the waves of magical force radiating from it so strongly that they were almost solid. His hair, crackling with static, stood on end, and as he reached out a hand towards the globe, tongues of cold, blue fire danced around his fingertips. "Incredible!" he breathed in awe. "Absolutely incredible!"

"Tom, get away from there!" said Lirenna anxiously, running over to him. "It might be dangerous!"

She grabbed his elbow, intending to pull him away, but a fat blue spark of electricity stung her hand, making her jump back in alarm. Hearing her cry of pain, Thomas spun around to see if she was hurt, and breathed a sigh of relief when he saw her examining her pale, slender fingers accusingly, wondering what had happened.

"I don't think it's dangerous," he said as he led her away to a safe distance. "Unless I'm very much mistaken, that's what's creating the gravity here."

"And unless I'm very much mistaken," added Jerry, "that's not all it does. It doesn't take an artifact that powerful just to make things weigh more. For the love of all the Gods, don't either of you cast a reveal spell here. We'd all be instantly fried to a crisp!"

Thomas agreed. Even from the edge of the room he could feel the power radiating from it, reminding him of the heat of a giant bonfire to which one was standing too close. "That was made by an immortal wizard or I'm a goblin," he said in wonderment.

"It reminds me of the Orb of Proofing," said Shaun, shading his eyes to look at it.

"Yeah," agreed Thomas. "Artifacts designed to throw a field of magic over a wide area are almost always orbs, and almost always made of either glass or crystal. It probably used the same fabrication techniques to make it, although on a much larger scale."

"What else do you think it does?" asked Lirenna, still staring, awestruck, at the globe through a narrow gap between her fingers.

"Who knows?" said Thomas thoughtfully. "However, I wouldn't be the least bit surprised if that's what's been keeping the air fresh all the time we've been here. Remember when we first arrived here the air was all stale, the trogs said it smelled dead. I bet that thing somehow sensed our presence and began freshening the air again for us."

"You mean it's intelligent?" asked Diana in surprise. "It can think, just like a person?"

"I wouldn't be the least bit surprised," replied the wizard.

They looked around the rest of the room, and saw that there were several tables and desks around the circular wall, each with a high backed chair in front of it. Several cabinets also hung on the walls at about head height, similar to the magically locked ones they'd seen earlier although many of them were larger suggesting that whatever they contained was larger than mere items of jewelry. Large, free standing wooden cabinets the size of wardrobes stood here and there, sometimes singly, others in groups of two or three, also magically locked, and a long wooden bench curved two thirds of the way around the glowing orb, about half way between it and the outer wall.

Thomas's attention was attracted to a number of wooden frames standing on the bench in which long transparent hexagonal crystals were sitting like bottles of wine in a wine rack. He picked one up, looked at it curiously for a moment, then put it back where he'd found it.

Shaun was more interested in the thick layer of dust on the floor, though, which contained no footprints except their own. "I don't know what this place is, or what it was," he said in puzzlement, "but it was obviously a very important place, the very heart of the whole complex. Why would they just abandon a place like this?"

It was a purely rhetorical question, to which he didn't expect to receive an answer, but to his surprise the answer came almost immediately. Jerry had been moving off to the right, to look at one of the free standing wardrobe-like cabinets, and was consequently now in a position to see that part of the room that had, up until then, been hidden from view behind the giant orb. He was examining the cabinet as Shaun was speaking and turned to make a comment but the words choked off in his throat as his eye fell on a row of chairs on the other side of the room. Sitting in each of the dozen or so chairs was a corpse. They were dressed in long, black robes with the hoods pulled low over their heads and they were leaning forward so that their upper bodies rested on the long, curving wooden bench.

He called their attention to the corpses, and the six of them crossed the room to have a closer look. "Here's the answer," said Thomas solemnly. "They didn't abandon this place. They stayed here, to die."

"But why?" asked Diana. "Why just give up like that?"

She gently pulled back the hood of the nearest body, revealing a bare skull leaning on its skeletal hands on the table. "Picked clean by rats," she said. "They seemed to go everywhere man goes. They probably stowed away in a consignment of food. Look." She indicated the finger bones, and looking closer the others saw that they had tiny toothmarks on them. They all shuddered.

Lirenna saw a small glass bottle on the table, just a couple of inches away from the bony fingers of one of the other skeletons. She picked it up and wiped the dust away from the label. "Poison," she said. "They killed themselves."

"But why?" repeated Diana.

Thomas was thinking hard. "Okay, what about this," he said. "The refugees dug this place out on a circular plan, with this place in the centre. Around it was their 'town centre' so to speak, and around the outside were the residential areas, the places where they spent most of their free time. Okay so far?"

"I think so," agreed Shaun, looking around the room at the four corridors that led away from it; the one they'd come in through and three others, arranged at ninety degrees around the room. "Everything we've seen so far seems to suggest that this place is symmetrical."

"All right," continued the wizard. "Now suppose this. The refugees knew they'd be stuck up here on Kronos for a long time, probably generations, and they were worried that they'd all go crazy being cooped up here for the rest of their lives in these rabbit warrens, so they also dug a number of huge park caverns. Four of them I'd bet, one at the end of each of those four corridors. Those caverns were landscaped and planted with grass and trees and stuff, so that people could go there and pretend to be outdoors. They probably painted the ceilings blue to look like the sky. Are you still with me?"

"Well, the existence of the other three is still pure conjecture," replied the soldier, "but assuming you're right, so what?"

"Well, suppose, just for the sake of argument, that those four park caverns became sudden death to anyone in them," continued Thomas. "I've got no idea what form that death might have taken, maybe it was a leak of poison gas or something. Everyone in the park caverns died, and if the only way of getting from the inner 'town hall' part of this place to the outer residential circle was through the park caverns, then that meant that everybody in here would have been trapped here, with no way of getting back to the residential circle. Now suppose that all their sources of food and water were in the outer circle..."

His voice trailed off. There was no need to go on. The memory of their imprisonment in the small steel room after escaping from the Underworld was still fresh in their minds.

"They wanted a quick, clean death," said Lirenna, looking down at the skeletons in pity and sorrow. "They wanted to die with dignity.

"Why didn't they go upstairs to the observatory?" asked Jerry. "They could have gone back to Tharthrough the teleportation cubicle."

"Not if the key's in the outer residential circle," replied Thomas.

Matthew thought of the cabinet in which he'd found the necklace, about how someone had been so desperate to break into it that they'd been able to splinter magically hardened wood. What if the necklaces were indeed magical, as Jerry had suggested, and granted the wearer protection against whatever death had struck with such violent force in the park cavern? He suddenly remembered with horror that he'd actually been wearing the necklace while he was in the park cavern, and his mouth went dry as he wondered what might have happened to him if he hadn't been wearing it. Is the death still there? he wondered fearfully, going damp with fear all over. He thought back to his passage through the park cavern and imagined being surrounded by poison gas, one breath of which would have killed him as horribly as everyone else in the cavern. He shuddered and wiped his sweaty hands on his legs. It was now more imperative than ever that he lead them back to the cabinet with the necklaces.

"Matt, are you all right?" asked Diana, seeing his distress.

Matthew cursed himself for letting it show, and with a rare burst of wisdom decided that the best way of covering it up was by telling the truth. Some of it, at least. "I'm fine," he said, forcing a smile. "I was just thinking back to when I went through that cavern, and wondering how close to death I was. What if whatever killed all those people is still around?"

Diana grinned, another rare event. "Well, that's what happens when you go wandering off by yourself," she said. "See you don't do it again."

"One thing's for certain," said Shaun. "We won't find the key here. Tom's right. If it was anywhere where these guys could have gotten it, they'd have gone back to Tharia. It'll be in the residential circle, if it still exists at all. Come on, we're wasting our time here."

"One thing first," said Diana, and she said a prayer over each of the skeletons in turn, beseeching Caroli to gather up their souls and let them rest in peace. She gave them one last sorrowful glance as Shaun led them out of the huge room and along the corridor heading eastwards, and then she turned her thoughts to the living survivors. Still trapped on the tiny moon. Unaware of everything that had happened down on Tharia over the past three hundred years.