As a warrant officer aboard the Nostromo, a spaceship from planet Thedus returning to Earth, Ellen Ripley was placed in stasis for the long journey home. The crew is awakened when the Nostromo receives a transmission of unknown origin from a nearby planetoid. Following their landing, an unknown creature infiltrates the ship, and kills every other member of the crew. Ripley is the only member to escape from the Nostromo prior to its explosion, which she deliberately commenced to kill the monster. However, she discovers that the Alien is also aboard the ship's shuttle, but expels it into space before putting herself in stasis for the return trip to Earth.