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.

Undercover cop Jim Raynor is a seasoned veteran. His partner, Kristen Cates, is lacking in experience, but he thinks she's tough enough to work his next case with him: a deep cover assignment to bring down the notoriously hard-to-capture drug lord Gaines. While their relationship turns romantic during the assignment, they also turn into junkies, and will have to battle their own addictions if they want to bring down Gaines once and for all.

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.