Ellen Ripley served as a warrant officer on the ship Nostromo during the ship's final voyage. When an unknown, alien lifeform attached itself to one of her crew, she attempted to follow quarantine protocol-her efforts were in vain, though, as the ship's AI MU/TH/UR had other plans.
Without quarantine, disaster struck. Using the ship's executive officer as a host, the alien burst from his chest and escaped into the bowels of the Nostromo. As the creature grew, its reign of terror continued, picking off crew members until only Ripley remained.
Alone and without hope, Ripley secured the crew's cat, Jones, and managed to set the self-destruct mechanism on the Nostromo without realizing the alien was one step ahead of her.
As the escape shuttle pushed through space, the small speck of light that was the Nostromo exploded into an expanding orange fireball. The shuttle jolted and rattled and then there was silence as the Nostromo receded into nothingness.
Unhooking her straps, Ripley began to prepare for the long journey back to the frontier when suddenly something stirred in the deep shadows of the shuttle-
Cautiously, Ripley inched toward the lockers where she put on her pressure suit. Then, as the alien advanced on her, she opened the airlock, ejecting the alien into the cold expanse of space.
With the shuttle secure, Ripley recorded her final report of the Commercial Starship Nostromo and proceeded to enter her hypersleep chamber. The dark fog of sleep slithered and coiled around her making her feel heavy and tired. She closed her eyes on one nightmare... only to open them in another.