On a dead oceanic shelf, an atmospheric processing station called the Spire has gone silent inside a spreading calcified reef. Three processor cores still regulate breathable chemistry across the shelf colonies, so a four-man salvage detail enters before the sector suffocates or is abandoned.

The Bone Bunkers are not predators that chase soldiers. They grow bunkers, alcoves, medevac niches, supply mouths, and defensive walls where frightened or wounded men will take cover, then vent calming gas and turn bodies into load-bearing structure.

Inside the reef, radio dies, thermal lies, motion reads nothing, and even sound is swallowed by the walls. When a tech steps into a false medevac niche and the route back begins closing cone by cone, the mission shifts from recovery to confirmed loss, with one survivor forced deeper through a place t ...