After her harrowing escape from the exomoon LV-426, Lt. Ellen Ripley's ship, the Sulaco, experiences a fire causing an escape pod to automatically jettison with Ripley and the surviving crew members inside. The pod crash-lands on Fiorina “Fury” 161, a desolate foundry facility and penal colony inhabited by male inmates with violent histories who have found quasi-redemption in a zealous form of Christianity. Upon arrival, Ripley is discovered among the wreckage by the colony's inhabitants and is initially met with suspicion and the potential threat of violence due to her gender and the disruption her presence causes their dynamic.

Ripley soon realizes that an alien organism may have also survived the journey from LV-426 and could be loose on the planet. She teams up with the prison doctor, Clemens, who becomes her ally, and the two begin to investigate the possibility. As the body count rises, the true nature of the threat becomes apparent, leaving Ripley and the remaining inmates to grapple with the dire situation. Forced into an uneasy alliance given their circumstances, they must figure out a way to combat the creature on a planet where no weapons are available, and isolation underscores their fear and vulnerability. Ripley becomes both the leader and the outsider in a desperate fight for survival against an unknown and lethal form of the alien species.