The story
Tidewell, as the Drift tells it.
The ocean world. Tidewell is ninety-nine parts ocean and one part rust. Its colonies stand on sea platforms, the old drilling and survey rigs of the migration years, lashed together over generations by catwalk and cable. Trawlers work the shallows and cargo haulers run between platforms. Jellyfish blooms light whole bays, and storms come in from three horizons at once.
The Choir. Down in the deep live the Choir: vast bioluminescent leviathans, seen from the surface only as slow light moving under the swell. Their songs travel on the old analog bands, and every trawler radio on Tidewell picks them up as long tones under the static. Sailors swear that sometimes they hear a song before it's sung: the radio carries a phrase, and seconds later the same phrase comes up through the hull. Nobody has proved it, and nobody on Tidewell is trying to. Nobody hunts the Choir either. Ask a trawler crew why and every crew gives the same answer: they're listening.
The post. Greywater Light stands on the Sliver, a knife of black rock that breaks the surface a few hundred metres from the oldest platform: the only land on Tidewell anyone has charted. The lighthouse is small, older than the platforms, and nobody agrees who built it. Its lamp was the colony's weather and distress beacon; it went dark in the Switch-Off and came back with a relay in its lamp room. The flame is painted on the bell buoy that rides off the rock's lee. Below the Sliver the rock drops away into kelp shelves and then the deep, and most of what matters on Tidewell happens down there.
The mark. Greywater Light signs with the flame riding the swell, as it rides on the bell buoy, and under the swell the long back of one of the Choir passing as a line of light. The tuning gap is a stretch of song from Maren's log, with the loudest note at twelve o'clock. The ring is the Choir's cyan on deep water, and its motto is the post's whole job: THE DEEP SINGS FIRST · SOMEONE WRITES IT DOWN ·
The keeper. Maren Holt keeps the light, and she logs the Choir's songs: time, bearing, depth and the shape of every phrase. She is the network's ears. She hears trouble first, as a change in the Choir or a change in the static, and the other posts have learned to take her calls before anyone else's. Her logs are the best record of the Echo that anyone in the network keeps. They are a record, not a proof, and she has never called them more. One song in them sounds like the sign-off on 142.59. She logged it the way she logs the others.
What lives there. Besides the Choir, there are seabirds on every rail and jellyfish blooms that drift in on the tide, and under the platforms the water is never dark for long. Lampfry, finger-long drifters that each carry a warm lamp of their own, travel in loose slow clouds that light the kelp like a town seen from the air. The trawlers net them by the ton, and a platform can live or starve on a season's run. Veilwings glide through the kelp shelves on wide wings like glass silk, veined with green light, and a crew that sees one cross the bow counts on a good haul. And now and then a burr drifts up out of the deep: a dark knot of needle spines with a coal-red light smouldering inside. Nobody eats a burr and nobody nets one on purpose. Crews call them bad luck, and when one fouls a net they cut the net loose rather than touch it. Down the Sliver's flank, where the relay's old sea cable runs from the lamp room into the deep, grows linebloom: a reef of glass-stalked polyps that took to the cable for its warmth and now covers the rock along its whole length. Its light is the line's: a calm cyan while the relay is sound, amber when it labours, a slow red pulse when it fails. Maren reads it like a barometer, and so does every crew coming home past the Sliver after dark.
Over the water. Between the platforms the sky has its own traffic. Rig-hoppers, squat rust-orange rotor lifters, run supplies from rig to rig with a container slung beneath them on four cables, and every trawler crew that can afford one flies a fish-spotter, a little float-footed autogyro that goes ahead of the boat to find the shoals. Long-haulers pass far up, and Pip Arro's Petrel comes in past the Sliver when Greywater Light has a part on order.
