“Mulin, you have a visitor.”

His concentration frayed; the frost that had been gathering in the air suddenly had a much easier focus on his fingers. He winced and bit off a curse, wiggling them with a soft crack of ice, and looked up as he rubbed his hands together.

Next to the day monitor was a figure he’d seen once in his life, and that a few hours before; but the grey robe he wore, clasped with a golden brooch bearing the rune for Storm, was even more distinct than horns that had wrapped around in three full turns with age. Archwizard Sulon. Mulin swallowed, and tried to sit up straighter.

“Rest easy, Mulin,” the Archwizard soothed, gesturing for him to relax. He pulled up his own chair and sat by Mulin’s cot. “I wanted to personally thank you for what you told us today. That last thing you said seems to have been the key to a puzzle. Exactly what it means, we don’t yet know; but now we have something to think about for the next few days. Or weeks, likely; maybe longer.”

“Oh.” The tip of his tail curled; he ducked his head. “It…”

“It was nothing, is that what you want to say? Mulin, to you it was a small thing – perhaps, it was something you considered to be expected of any citizen. But there are many citizens indeed who simply go from day to day, and keep their mouths shut on the things they think are inconsequential. They do not want to trouble the important people with their little fears. Yet sometimes those fears are significant; that was exactly the sort of thing we hoped to tease from your memory today.” A breath. “But that’s not the main reason I’m here. Ah, Physician… Jeris, is it?”

“Yes, Archwizard,” said the arriving, red-robed healer, smiling to be remembered.

“Is Mulin well enough to depart, do you think? I would show him a few things.”

“So long as you don’t plan to have him guest at another Assembly,” said the healer with a small, ironic frown. “What he needs most is rest; but he can do that as well elsewhere. I dare say returning home, when your business is done, will be the best thing for him.”

“Oh, very good. Mulin, I promised I would show you why we were so certain you hadn’t caused the problem. For this, I would like to show you around the heart of the font in some detail, and I also have some documents that might be instructive; would you like to come?”

To be shown around the mana font by one of the Archwizards themselves? Most young folk dared not even dream of such a thing; he grinned. “That would be splendid!”

“Splendid,” the Archwizard echoed. “I will wait for you in the corridor, then – and send a page to let your family know. It would not do to have them worry.” He bowed his head, and strode smoothly from the Halls of Healing – old, yes, but far from decrepit.

Mulin dressed in a hurry. Only at the last moment did he have the prudence to neaten his vest and straighten the brooch of his cloak.

Sulon was, as promised, waiting for him in the hall; he was alone, and carried a scroll case that he hadn’t had with him a few minutes before. Teeth flashed in a grin as he took in the youth’s eager expression. “Might I just say, Mulin, it’s truly a relief to see you bouncing back from your ordeal. Many in your position would be hesitant to go near the place again – to say nothing of practising magic so soon after such an event. I daresay the time you spent there, rudely interrupted though it was, has been helpful?”

“Y-yes, Archwizard.” Mulin ducked his head, tail curling again. “Mother insisted that I try. It’s not so easy as it was there, of course, but… so, so much easier than before.” They set off; Sulon was taller and thus could walk with a longer stride, but Mulin had enough energy to jog. Were they not underground, he’d have been only too happy to fly.

“The first time is always worst,” the elder Stormkin opined. “It’s the same way after an injury, Mulin, that keeps you from flying or walking. The first step, the first flight – those are hard enough; but if you’ve already been running or flying, and suddenly can’t… the first time you go through that, trying again is always, always hard. But so very worthwhile.”

“She had to bully me into it,” he admitted; and added, “But I’m glad she did.”

A soft, wistful sigh. “In a few ways, you remind me of my granddaughter,” Sulon mused. “A few years older than you, just starting with her own magic, so full of wonder to find out just what she can do with it.”

“Might I know her?”

“I don’t think so; she’s had her lessons in the opposite side of the city from your parents’ den. But I think you might get along. At any rate, that is an agenda for another time.” They had reached the winding stair that descended toward the Font; and so they started down.

“Mulin, imagine that all mana in the world is drawn from a vast well,” he said. “Like water through a wheel, it does its work as it descends toward that level. There are natural geysers of it here and there; the mana font, on the other hand, is like a great pump which lifts a vast flow of it high up indeed, and from there it spills down. Anyone who can touch mana can shape it during its course, tap the flow, work magic with it. Ah, but the Nexus… the Nexus is special.

“First, a thing to note. The outlet from the Nexus chamber goes straight into the reservoir – not to the rest of the city.”

Mulin blinked. “But… I thought the Nexus was the source…”

“The outer walls of it,” Sulon clarified, “are.”

They descended a moment in silence while Mulin absorbed that. “So,” he said at last, “the mana inside the chamber…”

“That is a completely separate flow from the rest,” the Archwizard explained. “Ah, pause here; this is actually a perfect time to show you part of the mechanism.” They had reached a service landing; now Sulon produced a keyring, unlocked the great iron door, and pulled it open, waving the youth through.

Once the door was shut, a short corridor led to a work of stone and silver and quartz, a thing he recognized as a major spell-form, though the details were beyond him. Not for long. “This,” Sulon explained, “is a mana channel. There are a few workrooms on the upper levels, you see, where a carefully modulated flow of mana is needed. Not so much as that at the Nexus itself, but better than the random ebb and flow. These channels regulate the upward flow They allow a certain amount of mana to pass, and no more; partly in this manner, the flow is kept steady. Though the output of the font fluctuates, this device… well, doesn’t exactly skim off the top; rather, it siphons from the deeper portions of the reservoir, where those fluctuations do not reach. What’s left after all these channels tap what they need is what gets distributed throughout the city.”

His fingers traced some of the spell pattern. “This channel is merely a repeater; a redundant step along the way, which helps ensure that no random flux enters the course of the channel. At the source is a channel which acts as a valve of sorts; when these workrooms are not needed, the channel is closed, and, like this one now, lies quiescent.”

Another part of the form. “But this is the key to what I have to tell you now. Have you taken much spell-form theory?”

“No, sir.”

“I’ll try to be basic, then. Imagine that the flow to the city is a great open canal. Anyone, anywhere, can dip into it and take their portion; this, combined with the variable flow from the source, means that the flow rate is hard to predict.

“But before the channel opens, there are a few taps, like this one. They take a very precise flow of mana – only so much, and no farther. If whoever is using the mana draws too much,” he tapped one of the sigils, “this pattern constrains the flow. In essence, the tap has no more to give; if the user wants more, they must draw from the open air.

“Within the Nexus chamber, there is no access to the open flow. The Nexus flow is vast, mind – far greater than any other of these channels. Nobody has ever been able to run the Nexus dry without there being some sort of mana storm to weaken the flow; there is enough power for even the full Assembly to channel to their greatest extent, and most of the time, all of it spills right back into the reservoir. Drak told us that you channelled a stunning portion of mana for a single caster – none below the rank of wizard, even at the height of their power, could draw so much – but still only one person’s worth. Most of the power was dumping right back into the reservoir as normal.”

“But when I tried to cut back on the power – ”

“That,” he declared, “was an accident of vastly unlucky timing. If the storm had taken place any earlier, you would have been in a power drought, but no worse off than you were. If you had been able to withdraw from the stream, and then the storm had struck, you would have had only the fire to contend with – assuming you hadn’t done something else to weaken that by then.”

Mulin thought it over. Nobody had actually tried to discuss it with him directly, but he’d heard people speculate that he and Kralin both being born Magekin was just the same sort of accident. If whatever it was that made Magekin had struck earlier, they would not yet have been in the egg; if later, either it would have found a different egg, or it would only have affected one of them. As it was, it had struck the entity that would divide and form them both; and then he and his twin had split from that same charged form.

So it was thought, anyway.

They continued their descent. Sulon pointed out the mana regulators that he’d been speaking of, some of the numerous patterns on the inner surface of the Nexus chamber. Back on the outside, he showed Mulin the various patterns which served as emitters of a sort; he invited Mulin to lay his hand on one, to feel the power they gave off. It was, of course, not nearly so intense as that from the Nexus stone, but there was a feeling of depth to it; this one would not feed as much mana to him, but it could be drawn from much, much farther away.

In a nearby workroom, Sulon laid out his diagrams, pointing out to him the various stations around Druumat that tapped the font and served as sub-fonts of a sort, feeding the more remote districts of the city. Mulin identified his home, not far from one of them; Sulon pointed out another, where his son and granddaughter lived, and indeed, it was almost straight across the city from his own, just two levels below the surface where his was six deep – of course; the Stormkin, more than any other Vhark, lived for flight, and craved dwellings near the surface.

“Spell-form work demands a great deal of mana tolerance,” Sulon explained as they returned to the inhabited levels. “I’m sure, if you don’t find something more to your taste, you would be quite welcome in that field – Four Winds, you could load-test many of the minor forms all on your own.”

“It looks like a fascinating field,” Mulin said, quite honestly. “I’ll be sure to study hard!”

A chuckle. “I’m sure you will, young one. But for now…” A heavy sigh. “For now, we must part ways. It’s been a pleasant and needed diversion, to spend this time with you; I hope it’s been helpful for you as well. But I must join my colleagues this evening, and try to figure out what caused this sudden storm. Be well, Mulin.”

“Health and long life, Archwizard,” he said formally, and bowed.

It had been a long and trying day. Rest at home, as the healers had said, definitely seemed to be in order.