In the aftermath of the Ishimura incident, the USG O'Bannon is dispatched by the Earth Government to investigate the derelict mining colony of Aegis VII. Among the crew are several individuals each with a dark history and unique skill set. As they arrive, they discover horrific evidence of alien infestation and begin to unearth the gruesome events that led to the colony's disastrous downfall. Their mission is complicated by nightmarish creatures that attack them and the psychological trauma inflicted by the mysterious Marker, an ancient alien artifact with mind-altering properties. In a series of flashbacks, the crew recounts their personal experiences leading to their fateful mission, revealing the toll the Marker has taken on their lives.

As panic and tension rise among the survivors, loyalties are tested, and true intentions are revealed. The crew faces both internal conflict and external threats as they desperately seek a way to escape the planet. They must confront not only the monstrous creatures but also the dark secrets and corporate greed that have contributed to the nightmare they find themselves in. The combination of relentless alien horrors, psychological breakdowns, and betrayals pushes each character to their limits, ultimately questioning their humanity and survival instincts as they fight for escape and a return to safety.