On the Kethys Refinery, a 2,800-meter deep-ocean extraction facility, a buried infestation has compromised the pressure hull and infected the crew. A three-soldier calibration team descends to the exterior gantry to manually realign damaged transformer coils and trigger an electromagnetic pulse that will sterilize the Trench Worms.

The Trench Worms are four-meter burrowers that fluidize solid seafloor sediment into slurry, sinking targets before pinning and dismembering them in absolute darkness. Every fragmentation kill creates reproductive seed-points, meaning any attempt to cut or blast the enemy only spawns dozens of new organisms that regenerate in fourteen days.

The team has only a two-second seismic warning before the ground liquefies beneath them. When the commander suffers neurological failure during the calibration and the e ...