In Metru Nui, Ko-Matoran were known for many things. Their devotion to learning was second to none. Their ambition to become Knowledge Tower scholars was incredibly powerful. Their attitude toward Matoran from other Metru was usually cold, and sometimes bordered on rude. Since they almost always had their attention focused on a tablet, a carving, or some complicated philosophical problem, they often missed things going on around them.

That was why none of the Ko-Matoran bothered to look up and notice Toa Metru Whenua hanging on to a tower for dear life.

"l thought you were good at this," Nuju snapped, scrambling to pull his fellow Toa back onto the roof.

"No, that's Onewa who swings around buildings," shouted Whenua. "I'm Whenua, who falls off them!"

With a mighty heave, Nuju succeeded in yanking the Toa of Earth back to relative safety on top of the ice-covered Knowledge Tower. Whenua immediately used his earthshock drills to dig himself handholds.

"Don't damage the crystal underneath," warned Nuju. "l should have gone with my first instinct and done this by myself. I knew what the consequences of this alliance would be."

"We worked together alright in Onu-Metru. Remember? Oh, I forgot, you ignore the past, don't you?" Whenua replied. "Besides, if you worked alone, you would probably just wind up like poor Tehutti."

The Onu-Matoran was standing on a nearby rooftop with Ehrye, his eyes wide and confused. Ehrye had a grip on his arm to keep him from wandering off. The four of them had encountered a patrol of Keerakh, the Ko-Metru Vahki and masters of strategy and tactic, and Tehutti had made the mistake of running. Keerakh Staffs of Confusion temporarily scrambled a Matoran's sense of present reality, making them so disoriented that they can't cause any more trouble. One swipe of a Keerakh staff and he lost all sense of time and place. Judging by the things he had said since, Tehutti thought he was back in the Archives cataloging a Fikou spider exhibit. Due to the Keerakh's efficiency and general lack of hesitation about using their staffs, it was not unusual to see confused Ko-Matoran wandering through the Metru, not sure where they were or what they were doing there.

"Are you sure the Great Disk is up here?" Whenua asked, getting cautiously to his feet. The winds were strong this high up and the Knowledge Tower rooftops had steep inclines. One slip and down he would tumble again.

"You were there when Nokama translated the carving," replied Nuju. "'In Ko-Metru, find where the sky and ice are joined.' Besides, Ehrye says it is near here, atop one of these Knowledge Towers."

Nuju stood at the edge of the roof and studied the gap between this tower and the next. His first attempt to travel by ice slide had failed miserably, so he was reluctant to do it again. Better to leap and rely on his crystal spikes to stop any fall.

Taking a running start, Nuju jumped into space. He had gauged his leap perfectly, arcing down close enough to the next tower that he could catch the side with a spike and anchor himself. Back on the other roof, Whenua looked on, frustrated.

Nuju raised his free spike and fired a blast of ice. When he was done, there was a thick, frozen beam in place between the two towers. "Wrap your arms around it and slide across," he instructed Whenua.

The Toa of Earth did some quick calculations, which included his new mass post-transformation, the thickness of the ice, and the velocity he would achieve just before he was smashed flat on the ground below. When he was done, he reported. "It will never hold."

"Yes, it will," Nuju insisted. "Probably," he added quietly.

Whenua jumped, caught the ice beam, and rapidly slid across the gap. He had made it halfway when the ice began to crack and splinter behind him. He struck the side of the building and dug in his earthshock drills even as the beam collapsed completely.

"Ko-Metru needs more chutes," Whenua muttered.

"Most Ko-Matoran don't travel by rooftop," said Nuju. "Look below."

Looking down was not high on Whenua's list of things to do, but the urgency in Nuju's voice left no room for argument. The Ko-Matoran far below looked like microscopic organisms, but those weren't what Nuju was pointing out. No, it was the half dozen Keerakh scuttling through the crowd and heading right for this particular Knowledge Tower that had the Toa of Ice worried.

"I thought we had left them far behind," said Whenua.

"Keerakh are efficient," answered Nuju. "We are not where we're supposed to be. It's their job to change that. Keep moving."

The two Toa Metru made it to the top of the tower. Whenua looked over the side and saw the Keerakh were climbing up the side of the building. "We have problems, Nuju."

"Worse than you know," said Nuju, pointing to the next tower. Three more of the Ko-Metru Vahki were gathered on its roof, waiting. They had scaled another ice tower, stranding the two Toa Metru. "Keerakh have found a way to take the element of chance out of tracking, the uncertainty out of pursuit. They have the uncanny ability to simply figure out where you are going and get there first."

"Have a plan?"

"Something like that," said Nuju, levelling his crystal spike and sending a blast of ice at Whenua. Instantly, the Toa of Earth was covered in a thick layer of ice from shoulders to knees.

"What are you doing?" Whenua demanded, struggling in vain to get free.

Nuju ignored him and turned to the Vahki on the opposite roof. "After a long pursuit, I have caught this thief from Onu-Metru. Take him to Turaga Dume for punishment."

The three Vahki looked at each other, obviously trying to figure out when the strange being with the twin spikes joined their side. With the closest thing Keerakh could give to a shrug, they sprang from their perch to take custody of Whenua.

In mid-leap, Nuju caught them with an ice blast and froze them solid. One swipe of his spike shattered the ice surrounding Whenua. "The Vahki have kindly provided us with a bridge. Let's use it."

The two Toa Metru ran across the bridge of frozen Keerakh to the next roof. Nuju looked over his shoulder to make sure Ehrye and Tehutti were well-hidden a few towers back, then turned his attention to Whenua. "Are you alright?"

"Well, I won't be in a hurry to visit the icier parts of the Archives for a while," the Toa of Earth replied. "Next time, give me a little warning."

"Alright. Hit the ground," said Nuju as he dove flat on the roof. Whenua joined him just as Nuju used his spikes to create a thin layer of snow and ice over them both. "Keep quiet," the Toa of Ice whispered.

Whenua could barely make out what was going on outside their icy shell. He spotted the shapes of the Keerakh reaching the top of the other roof. Half of them immediately went to work chipping away at the ice bridge while the other half crossed it in pursuit. One walked right over where the Toa lay, camouflaged.

Whenua started to rise. Nuju grabbed his arm and said softly, "Not yet. Wait."

"Wait? Wait for what?"

"You're the archivist," Nuju said quietly. "What do you know about Keerakh?"

"Let's see. Ko-Metru Vahki. Order enforcement technique is disorientation. Hard to hide from because they're always one…step…ahead of…" Whenua smiled.

"Exactly," said Nuju. "I do not know how they do it, but they do. So rather than run from them—"

"We follow them," Whenua finished. "And they lead us right to the Great Disk."

X X X

Of course, following Vahki was easier said than done. In their dormant state, Vahki occupied a circular hive, with one Vahki monitoring each direction. Though they appeared to be completely inactive, Vahki sensory apparatus never fully shut down. Any sound or movement was instantly detected. When Vahki traveled, they moved in much the same way, always with an eye turned toward the flanks and rear.

For that reason, Nuju had recommended that Ehrye and Tehutti be left behind. Tehutti kept ranting about misfiled Fikou anyway, and Ehrye was in no hurry to walk into a possible Keerakh trap. So the two Toa Metru traveled alone, relying on speed and stealth to keep up with the Vahki and keep out of sight.

Their journey ended at a central tower. The half dozen Vahki paused there and began to mill around. After a few moments, each Keerakh locked its four legs into place on the icy roof and settled in to wait.

Nuju frowned. "Of course, there is one problem with this plan."

"That's a change—you not thinking ahead," said Whenua. "Maybe what the Vahki need is a little disorder. Get me down from up here."

Nuju moved to the far edge of the rooftop and checked to make sure the Vahki had not yet noticed their presence. Then he used his elemental energies to create a thick pole of ice stretching from the roof to the avenue below.

"l was thinking more like pointing me toward a chute," said Whenua.

"This is faster."

"...Right. At least it will be over quick," said Whenua, getting ready to ride down the pole. "When you see your opportunity, get that disk. I'll meet you in Ga-Metru."

Nuju watched as the Toa of Earth slid down and vanished in the icy mist. Then he went back to watching the Vahki.

Down below, Whenua was doing his best not to get sick. He was moving much too fast, with no way to slow down. At this rate, he would succeed in distracting the Vahki by making a very large hole in the street.

On the rooftop above, Nuju was counting quietly to himself. When he reached 10, he launched two more bursts of ice from his crystal spikes. They arced over the side of the building and disappeared.

Whenua saw the ice bolts approach and then pass him. The next thing he knew, he was flying down a winding ice slide that had suddenly formed around the pole. The angle of the slide kept changing so that, little by little, Whenua's descent was slowed. He still hit the ground hard, but Nuju's calculations were correct. The Toa of Earth hadn't suffered any serious injury.

That's the second time he's surprised me today, thought Whenua. Hope it isn't going to become a habit.

He looked around. A few Ko-Matoran had looked up from their studies long enough to notice that a Toa Metru had just dropped into their midst. It was only a matter of time before one summoned additional Vahki. Whenua went to work, using his earthshock drills to cut a hole in the street.

Once the opening was wide enough, the Toa dropped down. As an archivist, he knew the underground of Metru Nui better than any of the other Toa. Immediately beneath the streets were mechanisms designed to help keep the Metru clean, protodermis pipes, and the occasional nest of rodent Rahi. Farther down would be whatever sublevels of the Archives had extended this far, and beneath that…beneath that, he preferred not to think about.

For now, he was only worried about the immediate sub-surface. Using one drill to bore through the street above, he used the other to disrupt the cleaning mechanisms, break the occasional narrow pipe, and generally make a mess. He made no effort to keep it quiet—the more noise the better.

He knew what would be happening above right now. Ko-Matoran would be looking around in wonder and annoyance at the disturbance. The sound would be traveling up to the sensitive ears of the Vahki. They would never be able to resist the chance to clamp down on such obvious disorder.

High above, the Vahki were proving Whenua right. First one, then two, peered over the side of the roof to see what was happening below. Unable to get a good look due to the icy mist that perpetually hovered over Ko-Metru, the Vahki squad left their positions and began climbing down the side of the Knowledge Tower.

Nuju waited until they were gone, then leapt to the next roof. He was sure the Great Disk must be there somewhere, but he saw no sign of it. He scrambled to get a little higher on the inclined roof and slipped, hurtling toward the edge.

Before he could put his crystal spikes to use, he had fallen over the side. At the last moment, he reached out and grabbed a huge icicle that hung from the ledge. It wasn't unusual to see icicles up this high, but he quickly noticed that this one was just a little different from the rest.

Frozen in its heart was a Great Disk.

X X X

Beneath the street, Whenua continued his labors, keeping an eye on the hole through which he had come. As soon as he saw Keerakh peering down through it, he knew it was time to be elsewhere. Revving up his drills, he punched a hole through the floor and then through the next level as well. Plunging through the gap, he tumbled into an Archives sub-level.

No Ko-Metru Vahki would ever find him down here. He took off at a run, following the winding corridors in the direction of Ga-Metru. If all had gone well, he would meet Nuju there with two Great Disks between them.

X X X

Toa Onewa and Ahkmou walked side by side through the Po-Metru Sculpture Fields, Vakama and Nurhii bringing up the rear. The journey had been made largely in silence, with the exception of Ahkmou giving directions to the hiding place of the Great Disk. They had already taken a few wrong turns thanks to the Matoran's "forgetting" exactly where it was concealed.

"It's not far," Ahkmou said.

"That's the tenth time you've said that," Onewa replied. "I'm beginning to think you don't want us to find the Great Disk."

"Of course I do," said Ahkmou. "Okay, so maybe I wanted them for myself at first. But now I realize that you six Toa need them to save the whole city. I wouldn't get in the way of that. Only, what are you going to do with the Great Disks once you have them?"

Onewa shrugged. "l don't know. This is Vakama's plan. I suppose we'll give them to him."

Ahkmou chuckled. "I see. So he gets all of you to go out and gather the six most powerful items in all of Metru Nui, and then you just turn them over to him? No questions asked? I wish I had thought of that."

I bet you do, thought Onewa darkly. "So who's this four-legged friend of yours? The one who likes pushing Toa into furnaces?" asked the Toa of Stone.

"He's no friend," answered Ahkmou. "We were…business partners. He asked me to get him the Great Disks. Doing it seemed like a better idea than having him angry at me. He didn't say why he wanted them."

"And you didn't ask. What did he promise you in return?"

"Protection," said Ahkmou. "Something we both need right now. Look!"

Po-Matoran were running from the Sculpture Fields in a panic. Only two things had been known to make crafters move that fast: quitting time and a rogue tunneler. Unfortunately, it was too early for work to be done for the day.

Tunnelers had been a problem in Po-Metru for as long as Onewa could remember. They were lizard-like Rahi, normally about twice as long as Matoran were tall, with an appetite for solid protodermis. As their name would suggest, they lived underground and used their claws to tunnel through solid stone. They had been known to dig up into warehouses and consume everything from raw protodermis blocks to finished tools. Rarely did they pose a real threat to the Matoran workers, but every now and then one went bad and began rampaging through the work areas.

Vakama and Nuhrii had caught up now. "What's going on?" asked the Toa of Fire.

"A little problem," said Onewa.

"A big problem," corrected Ahkmou.

The tunneler had emerged from beneath the surface into the middle of the Sculpture Field. It was bigger than any Onewa had ever seen, easily three times the size of a Toa. Worse, its scales were mottled with dark patches and its eyes were red. In a tunneler, both were sure signs of madness.

"Maybe I can scare it off," suggested Vakama. Before Onewa could stop him, he had lobbed a few small fireballs in the direction of the tunneler. Not wanting to hurt the beast, Vakama had aimed well over its head.

If the tunneler could have smiled, it would have. As the fireballs approached, it reared up on its hind legs and purposely let itself be hit. An instant later, it had transformed from a creature of scales and claws to a monster of flame.

"We're not in your Metru, Vakama. Fire's not the answer to everything," Onewa said sharply. "Tunnelers absorb whatever power you throw at them. We've gone from a menace to a catastrophe."

All around the creature, sculptures had begun to melt. Every step it took left a charred footprint in the soil. Even at a great distance, the two Toa Metru could feel the heat. "If that thing makes it out of the Sculpture Fields, all of Po-Metru could burn," said Onewa. "Let's see if it wants to play catch."

The Toa of Stone lifted a huge boulder and prepared to throw it. Vakama couldn't understand his strategy—most of the rock would melt before it ever reached the tunneler, and what was left wouldn't do any damage.

Onewa tossed the boulder. It began to glow and melt as it got closer to its target. But enough made it through that the tunneler had to bat the fragments away with its tail. As soon as rock met tunneler, the creature transformed again, this time becoming a thing of stone.

"Well, that helps a little," said Onewa. The tunneler brushed lightly against a massive sculpture, and the statue crumbled from the blow. "Or not."

"l have an idea, but we'll need Nuhrii and Ahkmou's help," said Vakama. He turned around and saw both Matoran were gone. A moment later, he heard the sounds of a struggle from behind one of the sculptures.

The Toa of Fire looked behind the statue. Nuhrii had Ahkmou pinned on the ground.

"He was trying to run away again," said the Ta-Matoran. "But he brought us here. Seems to me he should help us get out again."

"You're both going to help," said Vakama. "Here's what we're going to do."

X X X

The tunneler slowly blinked its stone eyes. Two of the little ones were still in its sight, jumping and yelling in a language it didn't understand. The two larger ones had disappeared. Ordinarily, there was no cause to harm little ones, unless they got in the way of a meal. But these two were annoying with their noise.

With a snarl, the tunneler lumbered forward to silence them.

X X X

"Now!" shouted Onewa. He slung his proto piton onto a nearby statue and he and Vakama swung from their perch high above. As they passed over the tunneler, Vakama unleashed a quick, intense fire blast at the ground.

Fire met sand right in front of the creature, fusing the ground into glass. Startled by the light and heat, the creature whipped its tail forward, striking the new glass surface. That was all it took for the tunneler of stone to change to a tunneler of crystal.

The creature spotted the two Toa Metru and started to take a step forward, only to be stopped by the sound of a sharp crack. Its new glass body wasn't strong enough to support the tunneler's size. Every move it made caused another hairline fracture to appear, so the tunneler wisely decided to stay still.

"That should keep it occupied until the Vahki arrive," said Onewa. "Then the archivists can decide what to do with it."

X X X

Onewa looked up at the tallest sculpture he had ever seen. It looked like an upside down mountain, balancing on its peak. Nokama had said that the Toa must seek a "mountain in balance" if they were to find the Po-Metru Great Disk. This certainly looked like the spot.

"It's up there," confirmed Ahkmou. "Embedded in a jagged hole near the top. Good luck getting it out."

The thought of the climb made even the Toa of Stone a little dizzy. He had no doubt he could get up there. It was getting down that might pose a problem.

"Are you sure you want to go up there alone?" asked Vakama. "l could—"

"No," Onewa replied. "If I have to be concerned about me falling, I don't want to have to be worrying about you falling too. Besides, if I don't make it down…"

Vakama nodded. Risking both Toa Metru would be foolish. Someone had to be left to get the Great Disk if Onewa failed.

The Toa of Stone dug one of his proto pitons into the side of the sculpture and began to climb. Vakama, Ahkmou, and Nuhrii watched him as he slowly ascended, each alone with his thoughts.

Onewa moved slowly, but steadily. His new body was far stronger than his Matoran form had been, but still his shoulders and arms already ached from the effort. And there was still so far to go.

His thoughts drifted back to the Great Temple and the moment he and the others had become Toa. He had certainly never imagined, when he brought the Toa stone there, that his whole life was about to change. Nor would he necessarily have picked his five fellow heroes of Metru Nui. Vakama was too much of a dreamer, Nokama seemed a little stuck on herself, Matau was simply annoying, and Nuju and Whenua argued constantly.

Still, they must have been chosen for this honor for a reason. Just as a Po-Metru crafter carefully selected the right tools for a job, so the Great Spirit Mata Nui must have had a plan in mind when he chose the six. But what it could be, Onewa had no idea.

Then an awful thought struck him. What if they were not the Matoran meant to become Toa? What if there had been a mistake? An accident? What if one or more of them got Toa Stones when they were not meant to do so? What would that mean for Metru Nui?

The idea disturbed him so much that his hand slipped off his proto piton. He caught it, just barely, and decided to stop worrying about what might have been. Things were the way they were. If a crafter got handed a badly made tool to carve, well, he worked with what he was given. Onewa would have to do the same thing.

He was nearing the top now and could see the Great Disk. Getting it out without bringing the slab of protodermis down on top of his head would take skill.

Onewa planted one proto piton, tested to see if it was firm, and then let go of the other. He took hold of the Great Disk and gave a tug, but it wouldn't budge. Another, and another, and still it wasn't going to move.

The Toa of Stone saw only one chance. He was going to have to use both hands. He crawled as far up to the top of the sculpture as he could and let go of the piton. He grabbed the Great Disk with both hands and pulled with all his strength. It gave just a little. Then a little more. One more tug would do it—

It was free!

Onewa felt a split second of triumph. Then he realized the slab was teetering in his direction. That was the good news. He was also falling to the ground, far, far below. That was the bad news.

Desperately, he reached out and grabbed one of his pitons. The force of his fall tore it loose from the sculpture, but at least now he had a tool. Now if only he could think of something to do with it.

Down below, Vakama watched Onewa's fall with horror. None of his disks would help in this situation, and melting the slab wouldn't save the Toa of Stone. But there had to be some way his elemental power could help.

Then he remembered something from his lifetime spent around heat and flame. He reached out with his Toa energy and began to heat the air beneath Onewa. Hot air would create an updraft that would slow the Toa's fall, Vakama was almost certain. It wouldn't save him, but it might buy him time to save himself.

Onewa felt his fall slowing slightly as a blanket of warm air surrounded him. He didn't know if it was Vakama giving him this chance or something else, but he was determined not to waste it. He slung his proto piton and caught it on part of the sculpture, twisting his body so he would swing rather than just stop abruptly. The sudden deceleration still felt like it would tear his arm off, but his new Toa strength won out.

He paused to catch his breath and make sure the Great Disk was safe. That's when the shadow fell on him. Onewa looked up to see the massive slab falling right toward him. He dove headfirst off the sculpture. He tossed his piton ahead of him, felt it catch on the sculpture, and swung around and down. It was now only a short drop to the ground. Onewa hit the sand and rolled, grateful to be back on solid ground.

Then the shadow came again, and he heard Vakama shouting, "Watch out!"

The huge slab of protodermis crashed to the ground with a force that sent tremors throughout Po-Metru. When the cloud of sand finally cleared, there stood Onewa, unharmed. Miraculously, the portion of the "mountain" that had come down on him contained the hole that originally housed the Great Disk.

From his vantage point, Vakama smiled. Someday, if Onewa allowed it, this would be a wonderful tale to tell.

X X X

But, while the Toa gathered the Great Disks, the Morbuzakh continued to tighten its grip on Metru Nui. Vines and trunks grew from the ground, shattering glass, crumbling buildings, knocking over towers, and destroying homes. More appendages grew even out of the sea to surround, remove and claim portions of the Great Temple. And still more of the plant dragged careless Matoran helplessly off into the shadows.

Jala, a Ta-Metru captain, ordered a rank of Ta-Matoran to launch a flurry of Kanoka at the Morbuzakh section coming at them, but the plant suffered only minimal damage. The troops changed to freezing and shrinking disks, which had stronger effects, but more attacks from the plant came from behind. Eventually the Matoran were overrun, forced to retreat and back away.

It was clear that not even the Vahki could overcome the power of the Morbuzakh. Two Vahki guards had responded to a disturbance in the gardens of Ga-Metru. Initially finding nothing, they moved in to search, only to meet a surprise attack by the camouflaged foliage. The vines grabbed them and lifted them high, and powerless, into the air. There, short work was made of the robotic enforcers.

Now that the Toa had the Great Disks, their task was just beginning.