Our trade, plainly put, is river-engineering for fire.
When the Flaming Mountains reignited, eight hundred li of earth-fire had no old bed to follow — the ancient lava channels froze solid three centuries ago — so the new magma shoved everywhere, and wherever it shoved, ruin followed. That Scorched-Earth Keep survives with fire on three sides, it owes to the lizard clans' diversion corps: raising weirs, cutting channels, walking the lava down its proper roads to congeal in the empty valleys.
The boy's great channel-to-the-sea project was the masterwork of a century. My corps, his calculations, the Holy Infant King's control of the burn — three hands together turned the fiercest trunk-flow away from the Keep, and now the children nap against the town wall.
That is the public ledger. Today I speak of the private one — the account only the corps itself knows.
Every diversion hand learns it early: magma is alive. Not alive as a yao is alive — alive with law. It has a pulse.
The deep magma rises and falls as one body at fixed intervals, like the earth breathing. The old marshals' verse: one rise and fall is one breath; nine breaths are one measure; while the measure holds, the fire is at peace. Our shifts, our cuts, our weirs — all are set to that pulse. In my hundred years of service, for ninety-seven the pulse was steady as an old tortoise's heart.
The change came these three years.
First the pulse quickened. Nine breaths to the measure became eight; eight became seven. The old hands lay against the channel walls at night, listening, and their faces went grey — a quickening pulse means the earth-fire is straining. But straining toward what? No signs of eruption. No new vents. All that force held down in the deep.
Then the pulse changed its voice.
An honest earth-vein beats muffled and round: DOOM… DOOM… like a great drum struck through cloth. What rises from the deep now comes sharper and faster: doom-doom, doom-doom-doom — have you stood near an army's drums? The cadence they beat just before the charge?
Identical.
I kept it quiet, took only my three sharpest-eared veterans to the floor of the deepest channel, and we listened three nights. On the third, the eldest — diversion men since his grandfather's day — climbed out shaking to his scales. Marshal, he said. That is no pulse.
That, he said, is drill.
The deep fire is rehearsing to a rhythm — the same sequence, over and over: gather, surge, recover. Gather, surge, recover. Like troops at their manual of arms, perfecting a single maneuver. What maneuver? An army of fire, drilling the charge — charging where?
I reported to the Holy Infant King. He went down grim-faced, listened one night through, and coming up asked one question: Marshal — how deep can your channels reach?
I said: wherever magma can go, my channels can follow.
He said: good. Cut a listening channel. Straight down. Divert nothing — only listen. Every ten days, record the drum-cadence and send one copy to me, one to the boy travelling west.
The listening channel is three levels deep now, and the cadence-records make a thick stack. The trend is a single word: faster.
Three years ago, nine breaths to the measure. Today: four.
What happens when it reaches one? I don't know. I know only a soldier's common sense:
war drums are never beaten idly. A drum is beaten because, someday, there is to be a charge.
And the veterans on the lowest level report that within the deepest cadence, this past half year, something new has crept in —
an echo.
Somewhere in the far, far west, another drum answers it. One urgent, one measured. One asking, one replying.
Two drums, agreeing on a date.
So when the boy went west I sent him the six best brothers of the corps, and stayed to keep the channels and the drum-log myself. At parting I gave him the plain truth:
child — while you race along the surface, something below is racing too.
Before the drum reaches one breath to the measure — find the western drum.