The Third-Year archives smelled of damp vellum and dried ink. Row after row of oak slates stood racked against stone, each one tagged with twine and filing ink that had gone brown with age. High above them, the tall arched windows let in cool morning light along with the rhythmic, heavy thoom of courtyard drills three floors below.
Cade's voice carried through the stone, calling out formation counts. Then the heavy impact of his fire-bursts rattled the glass in its lead frames — clean, massive output, but hit with a jagged, aggressive cadence that made the lead cames vibrate a fraction of a second late. Every burst landed. None of them landed easy.
At the corner table, two cadets from Squad 4 were stowing their styluses into leather wraps, their evaluation slate already filed at the edge of the desk.
"Ninety-eight," the taller one said, his voice quiet but brimming with satisfaction. "Highest score in third-year section."
"Should've been a hundred," the second muttered, wiping charcoal from his knuckles. "We rushed the final seal on the second phase. I felt it slip."
"The seal held," the first replied. "Target went dead right on the mark. Manual says four seconds for containment, we did it in three and a half. That's not rushing, that's clean."
Leo didn't look up from his slate, but he heard them. They were right. Their methodology was textbook — precise, repeatable, and completely aligned with the handbook's tables. According to the Second-Year manual, a four-erg kinetic pulse delivered without a containment matrix produced one of two predictable outcomes: a two-erg rebound back through the frame, or a two-erg residual shockwave down through the target base. You paid one way or the other. The energy had to go somewhere.
Leo picked up his stylus, his thumb black with rubbed-off carbon, and looked down at his own numbers.
He had copied the proctor's gauge reading from the morning's practical.
Zero.
Not two ergs. Not a fraction of an erg. Absolute zero. Needle hadn't even twitched.
He scratched out his third attempt at calculating the red clay's absorption capacity. The math was simple enough. Even if the damp soil beneath the pedestal had taken the entire load, the force required to kill a four-erg pulse instantaneously should have split the clay wide open. The pedestal ought to have sunk two inches into the dirt and thrown up a lip of cracked earth around the iron feet. The air should have still been humming.
Instead, the frame hadn't even quivered. The red flare had dropped to dead grey in four seconds and the field had gone silent.
Leo leaned back, staring at the blank line where the residual force equation should have balanced. His model wasn't just slightly off. It was missing an entire term. The left side said four ergs in. The right side said zero out. Nothing in the Second-Year manual allowed for that.
Heavy boots scuffed against the floorboards.
James walked past the alcove holding a thick, water-stained maintenance ledger Squad 7 had borrowed for the lower aqueduct detail. The cover was warped from damp and the pages stuck together at the corner. He set the heavy book on the returns desk with a dull thud, turned, and started toward the stairs.
"The clay capacity isn't high enough," Leo said before he could stop himself.
James stopped, his hand resting on the wooden railing. He looked back over his shoulder.
Leo tapped the tip of his stylus against the margin of his slate, where three different calculations had been wiped to grey smears.
"Four ergs enter the iron," Leo said. "Without a matrix to hold it, the frame has to yield or the soil has to fracture. The clay density in the primary field isn't high enough to take that load in four seconds. Even saturated. I ran it three times."
James looked at the scrawled numbers on Leo's slate, his posture loose and completely unbothered.
"You're treating the dirt like a box," James said.
Leo blinked. "It is a container. Force enters the structure, the structure transfers it down. That's how the circuit is drawn."
"The dirt was already taking the weight before the pulse hit," James said plainly. "Luna didn't put force into it. She just didn't let the pedestal pretend it was floating."
Leo stared at him, his stylus hovering an inch above the slate.
"That's not how the circuit is drawn," Leo said.
"Then the drawing is wrong," James said. He looked toward the hall clock, where the brass pendulum was swinging toward the midday mark. "Kara's going to eat my bread if I don't get to the hall."
He turned and walked down the stairwell without waiting for an answer, his footsteps fading into the lower corridor.
Leo sat alone in the alcove. The Squad 4 cadets had already gathered their things and left, their quiet laughter trailing down the hall toward the stairwell. Out on the courtyard, another heavy thoom shook the floorboards as Cade drove a second fire-burst into the straw targets, and the old glass rattled again in its frame.
Leo looked down at his slate.
He picked up his rag, wiped away his third calculation until the slate was clean, and drew a single clean line through the word Container where he had written it at the top of his working.
Beneath it, in small, precise letters, he wrote: Variable.