A/N: Finally, after ages sat around as an idea being constantly re-written, I've started to get this old idea into order.
It follows on from my story Master of the Dark. I hate doing sequels that you have to read the previous stories to understand, but in this case you'll definitely find it a lot easier to understand if you do read Master of the Dark first.
Several of the characters that didn't seem to have much point to them in the previous story make that point known - eventually - in this one, some things get explained, and some new parts of the Dark Arcology are seen.
(If you don't know or can't remember what an Arcology is, grab the first chapter of Master of the Dark and read the notes I left in it. I explain it there.)

Anything else... oh right. You know what? I don't own Kingdom Hearts. Might wish I did sometimes, but I'm afraid I don't.
So, with that - Onward ho, and let's see where this story takes us.

Jamie entered with a gift of silence that no one else seemed to be able to match, taking in the room as he approached the desk.
Along one side were bookcases, filled from floor to ceiling with books, along with a door to other rooms in these quarters. In one of the supporting beams was the hilt of a sword, a small part of blade sticking out. It was Masamune, and the only remaining evidence of this room's previous occupant. No one had asked where the other end of the blade had finished up.
The other side of the room was slightly more personalised. The walls were a two-tone of dark blue on top and red on the bottom, a thin band of gold separating them. Hung on them were pictures of the occupant, some with people Jamie knew, others he'd only heard of. In a few it seemed almost like there was a twin.
On a table, with various paraphernalia arranged around it, was the signature keyblade. It seemed occasionally to shift through various alternate forms, but always returned to the standard keyblade.
Then ahead, just in front of the darkened windows, was the high-backed swivel chair, currently facing the window, and the plain desk, paperwork scattered over it somewhat haphazardly.
He waited patiently, not wanting to disturb.
After a few moments, the chair turned back again, and it's occupant began to tend to the paperwork for a moment, before glancing up at him. A few moments passed before he acknowledged his guest.
"Jamie," he murmured.
"You sent for me?"
"Who are you working for at the moment?"
"Right now? Sand."
"Anything important?"
"Nothing that can't wait."
"Good. The Council expressed an interest in something recently, and it's something I'm curious about myself. Your record of successful investigations speaks for itself, so naturally I want you to handle it."
"What's the case?"
"You know the Arcology and it's residents all take from the same unnamed, unknown power?"
"Who here doesn't?"
"Find it's source, Jamie. We want to know what supplies it, what the absolute limits of it are, and more importantly if it's going to run out."
"You're telling me no one's ever investigated this before?"
"Apparently not, more than reason enough to have it seen to already."
Jamie considered this, then asked, "If I need anyone?"
"You know the procedures, for those inside and out of the Arcology."
"Anyone not within my authority, I mean."
"Talk to Sand. He's your First, he'll know what to do. Anything else?"
"I'll let you know if anything else comes up."
"Go to work then."
"At once, Grandmaster," he replied with a respectful nod.
"I wish people would call me Sora again," The Grandmaster complained as Jamie left.

Disney Castle
The Throne Room

"Your Majesty."
"It's been a long time since you showed up."
"I know. I don't mean to show up unannounced, but it's a matter of some urgency."
"Oh?"
"Sora is missing, Roxas is back and also missing and Donald and Goofy have no way of getting to him. Kairi's worried too. Some months ago, Sora promised her he'd stop by from where he claimed to be, but hasn't. It's been nearly a year since then."
"Where did he claim to be?"
"The Dark Arcology – but I know that place to lay in ruins. I've been to them myself."
"Go to Kairi. She knows both of you well."
"What do you want me to do?"
"I leave that in your hands. Don't worry about Donald or Goofy. I'll look into things and tell them what I want them to do."
"Wouldn't it be better for them to stick with Kairi too?"
"No. You're more than capable of handling things, my friend. Split into two groups, no matter what you two decide to do, we stand a greater chance of solving this."
"Kairi isn't going to like that."
"That's why I want you to be there for her. She'll need someone."
"I'll see to it, your Majesty."
"Didn't I tell you to call me Mickey?"
"I guess it's been so long, I forgot."

Twlight Town

Kairi was pouting. Anyone who'd kept up with what was going on knew why this was.
Almost a year ago, Sora had been taken into some mystery-shrouded place called the Dark Arcology, risen up in it's ranks, and called on some of it's residents to break an attack of Heartless on the town. He'd promised to visit her when his work there allowed, but no one had seen any sign, nor received any word from him.
To make things worse of late, Donald and Goofy had received a message from King Mickey that they had steadfastly refused to discuss or let her help with, then slipped out in the night so she couldn't try and join them.
Because of this, nothing seemed to be able to bring her out of it at all. She found fault with everyone or everything. The town wasn't as interesting as it used to be. No one was as good as they normally were. She even criticised food that normally she would have been perfectly fine with.
All because Sora hadn't shown up.
Now she was sulking, and trying to decide what to do.
She could go after Donald and Goofy, but no one had seen them on the way out, leaving her with no trail to follow.
She could go looking for Sora herself, and brave what risks came her way. She'd fought for him before without his aid, but that had been with Donald and Goofy beside her. Alone was a different prospect entirely.
There was a hesitant knock at the door to her room.
"What?" she snapped irritably.
"There's someone who wants to see you," a voice called back. "He says he knows you."
Could it be Sora? Could he finally have found time at last?
"Tell him to come here quick," she told the door, getting ready to launch into a rant at Sora. She'd had plenty of time to work on it.
"Mind if I join you?" a more familiar voice asked her from beside the window. Sitting in the chair beside it, looking for all the world like he'd been there all along, was Riku. "You did say you wanted me to come in quickly. You look a little out of sorts."
"I was expecting someone else."
"I know – Sora."
"He was meant to have shown up by now. I'm almost ready to go looking for him myself."
"You don't look like it to me. Your things aren't even tidied away."
"Well... not that kind of ready. I was thinking about it."
"Only thinking?"
"I don't know what to do, Riku. He's gone off without me again, and just last night Donald and Goofy sneaked out as well."
"So what's keeping you here?"
"You know yourself how easy it is for me to get caught up in the wrong kind of things. You did it yourself, remember?"
He looked faintly embarrassed and answered, "Sorry Kairi, but I had to do what I did. It's all behind me now. Honest."
"Really?"
"Actually, that's sort of why I'm here. Not to do that again, I mean. I thought I'd try it Sora's way instead. Saving people and all that. It's not really what I do best, but I can at least try, right?"
"Oh, Riku. You'd do that for me?"
"Of course I would. Sora and I might not get along, but it's not as fun when he's not around to annoy."
"Riku!"
"I'm just teasing. You're the one running this search for Sora, you know. I'm just around to do what you can't."
"That's not helping much."
"Maybe not, but I know where we can start. Somewhere called the Dark Arcology, wasn't it?"
"How do you know about it?"
"I've met it," he answered shortly, contempt briefly flicking over his face. "I didn't want anything to do with it. Some kinds of darkness are better left alone."
"So you know where it will be?"
"No, but I know where it used to be."
"What good is that?"
"We won't know until we get there, will we? It gives you somewhere to start though."
"What would I do without you?"
"Stay in here and pout some more? You look cute when you do that."
Kairi went flush, but pretended not to hear.

The Dark Arcology
Grandmaster's Quarters – Floor 199

Sora didn't like the extravagance and opulence of the Grandmaster's Quarters, but they were his now. He'd taken on Sephiroth yet again, this time as the previous Grandmaster of the Dark Arcology. Unlike the last times, he'd had no choice but to kill him, something that still bothered him. It wasn't in his nature to do something that extreme, but the alternative was to leave him in power – something he couldn't have tolerated, given everything he'd done.
Many of the Arcology's long-time residents had objected at the changes he'd brought round, throwing out some of the more unpleasant practices some held in place, and changing those he couldn't remove so they were at least better than they had been. The Council effected most of the changes with the same ruthless, unyielding commands that he issued, though he preferred not to have to do that personally.
For the more serious matters, if he couldn't handle it himself he sent one of the two Advisors – the two highest ranked individuals in the entire Arcology before him – to handle it. One was an ex-Council member, Sab, who took the more distant approach, manipulating things without getting directly involved unless she had to. The other was his own Nobody, Roxas. Unlike himself and Sab, Roxas didn't let anything stop him from getting things done.
The result had been a sharp turn back toward the original principles on which the Arcology had been founded. It was no longer as Dark as it used to be, and in some corners the name had fallen into disuse in favour of 'Sora's Arcology'. The original aim was more actively pursued now, searching out, tracking down and retrieval of any item that held unusual powers, no matter how strange or unusual. The Arcology had an entire floor dedicated to these objects, named the Reliquary. He'd once glanced into the catalogue of all objects inside, and found that there were artefacts of all kinds, shapes and sizes to do almost any task. The last best estimate of how many were there numbered in the millions, and there was a separate catalogue twice as thick of relics and artefacts as yet undiscovered but known about.
The Dark power at the core of the Arcology remained though, it's source unknown, it's link to the Arcology and it's residents even more unknown. No one could understand why no previous attempt to study it had been made, though Sora privately suspected that any Grandmaster before him who had used it to his own ends just wasn't interested – as long as it still worked for him.
For now, he lounged in one of his favoured rooms, made to resemble the Destiny Islands he'd left behind so long ago. It took up a fair portion of the floor, but that didn't matter to him. It was better than leaving it dedicated to some of Sephiroth's... perversions.
"Reliving the past again?" Roxas' voice, so similar to his own, asked.
"Taking a load off," he answered, not getting up. "Did you talk to Nighthawk?"
"Talk," he snorted. "She wouldn't listen to me unless I ordered her to. She told me to butt out of her business. What she does as a First is her concern alone, she said."
"You didn't leave it at that, did you?"
"Of course not. I handed her position to one of Axel's rogues instead, sent her down a few ranks, then put her to work on the Visitor's Entrance."
"The Visitor's Entrance? Seriously? Roxas, we don't get any visitors here."
"You're telling me. But it keeps her out of trouble."
"So that's where you've been sending the troublemakers, huh?"
"Why not? At least it means if we ever do get a visitor, the place will be staffed."
"I guess so. I was thinking of getting rid of it myself. Trying to cut back on wasting resources."
"Do that too much and you'll have too many people without things to do. There's something else Axel mentioned though."
"What?"
"One of his people is on the trail of a group of our people that left the Arcology and went rogue. They managed to haul in one of them, and uncovered a little plot." He handed Sora a bit of paper. "Here's what we uncovered."
"Paperwork? Roxas, I'm trying to get away from it in here," he protested, but took it anyway. His expression grew steadily more serious as he read. Finally, in a quiet tone he said, "You know what this says, don't you?"
"Naturally."
"Go to Mickey. Do whatever you have to do, but don't let this happen to him."
"You know he won't know who I am."
"You're a Nobody, which exempts you from the normal rules remember? You get to choose if they apply to you or not."
"That's not what I was talking about. He's never met me."
"Well explain it to him then. Like I said, do whatever you have to do. The last thing anyone needs is him out of action."
"An order, Sora? From you?"
"Get to it, Roxas, or I'll do more than just order you to do it. This is important."