After drifting in space for 57 years in cryostasis, Ripley, the sole survivor of the commercial spacecraft Nostromo, is rescued by a deep-space salvage team. Upon her return to Earth, she discovers that the planetoid where her crew first encountered the deadly alien species is now home to a terraforming colony known as Hadley's Hope. When contact with the colony is mysteriously lost, Ripley reluctantly agrees to accompany a unit of high-tech colonial marines on a rescue mission to investigate the situation. Still haunted by her previous encounter, Ripley is driven by a need to confront her fears and ensure that the aliens are destroyed.

The team arrives at Hadley's Hope to find it deserted, with signs of a violent struggle everywhere. As they search the desolate settlement, they slowly piece together the horrifying fate of the colonists, confirming Ripley's worst fears. They encounter a traumatized young girl named Newt, the only apparent survivor, who provides insight into the aliens' nightmarish onslaught. With the terraforming station compromised and the situation increasingly dire, Ripley and the marines must work together to secure a means of escape while facing a deadly and relentless enemy, superior in number and adaptability. Their survival hinges on Ripley's experience, quick thinking, and the marines' firepower, as they confront the ruthless bio-engineered creatures that spared no one in their previous encounter.