Insect-like aliens invade a small town. The local teenagers have been watching a sci-fi marathon in the local theater, and from those films they get ideas on how to fight the creatures.

Ripley, the sole survivor of the Nostromo's deadly encounter with the monstrous Alien, returns to Earth after drifting through space in hypersleep for 57 years. Although her story is initially met with skepticism, she agrees to accompany a team of Colonial Marines back to LV-426.