On Brine Lock Seven, a flooded deep-ocean mineral extraction platform on an alien ocean world, a Kitesail infestation has overrun the lower galleries and killed the human work crew. A penal squad of seven pressure-suited soldiers is deployed from the orbiting ship *Retributor* to descend into the flooded facility, reach the ballast control room, and manually override the emergency flood sequence before the station is lost.

The Kitesails have adapted to the platform's flush-phase pump cycles, using the violent brine surges to travel through maintenance channels and punch through floor grating to extract prey from below. The squad attempts to cut their way through the galleries and reach the override console, but they find the controls destroyed and the survivors trapped below, forcing a tactical retreat as the alien hunters use the machinery ...