The alarm doesn’t sound like a drill. It sounds like a wet finger on a glass rim, three long tones, then a pause, then three more.

You sit up in your bunk on habitat Nereid and bump your hair on the pipe that always waits there. The pipe is cold. Everything is cold if you give it a second. Nine hundred meters of black ocean sit on the hull like a mountain that learned to flow.

TIDE, the habitat computer, speaks from the ceiling in a calm voice that does not care about your heartbeat.

“Submersible Sprat missed check-in. Last known: vent field, two kilometers bearing two-four-zero. Surface ship Gannet reports sea state too high for crane ops. Commander Vargas to control. Junior Aquanaut, you are up.”

You are the junior aquanaut. This is your first real tour that isn’t a pool with a proud sticker at the end. Last month you packed wool socks and pretended not to be nervous. This month the sea has a timer.

Through the tiny port, there is no view. There is never a view at this depth, not with eyes. The lights on the terrace make a small gold coin of dust and then give up. Fish, if any, are rumors.

Your badge is still stiff at the corners. It says JUNIOR AQUANAUT and a number you have memorized like a secret. Down the corridor, one way is the sonar shack—screens, headphones, Dr. Yuna Sato already talking to ghosts that are really echoes. The other way is the moon pool, where Reed Malik keeps Minnow the work sled from floating away or falling into the mud.

A second voice, human, cuts over TIDE: Commander Sol Vargas, already moving. “This is not a movie. Hands on rails. If you guess, guess after you look.” You swallow. Guessing is exactly what they warned you about in the classroom with the sticky chairs.

Paz Ortega is on Sprat. Paz tells terrible jokes and labels tape with tiny stars. Paz is not a drill.