When the Ishimura brings up a chunk of the planet for mining purposes, the colony's power goes out and two miners, Colin Barrow and Glenn, set down after a fly-over and begin to investigate a seemingly deserted part of the colony.

Hostilities begin to break out as members of the religious group, the Unitologists, beg for a glimpse of the Marker, a key icon in their religion. A week passes and a rash of violent attacks between the miners and other crew begin to rise in numbers. They discover an object referred to as a ' Marker' on the planet's surface the artifact is later brought aboard the Ishimura by orders of Captain Mathius. One of them notes chemical weathering on the walls and another takes note of what appears to be a claw mark.

Going back in time, three patrolling inspectors in RIGs move to inspect unusual seismic activity on the planet surface. A screen crackles to life as an exhausted Alissa Vincent gets in the chair in front of the recording device, explaining the fall of the Ishimura due to an infestation of parasitic alien-organisms brought about by an artifact discovered on the surface of Aegis VII and tells the recipient of the message that the Ishimura and the artifact must be destroyed.

Dead space downfall cast