A cargo ship (Nostromo) is ordered by their company to investigate a strange crash landed ship. After their shuttle lands a three man away team onto the ship, they discover a face-hugger alien who attaches itself to the second officer's (Kane) face. Back on the ship, the doctor (Ash) cannot get the alien off. Shortly after, it is found that the alien has detached itself and died. Kane seems fine, but during a meal his chest explodes and releases a baby alien who was growing inside of him. The remaining crew make different plans to kill the Alien. Every time a member of the crew is killed including the captain. Third officer Ripley (played by Sigorney Weaver) takes command of the ship. She finds out on the ship's computer that the company wants Ash to deliver the alien to earth where it can be researched. Ash confronts and attacks Ripley. When the other crew members arrive they manage to cut off Bishop's head and discover him to be an android who is loyal only to the company. Ripley and the two surviving crew members make preparations to escape on board the escape ship, then blow up the Nostromo to kill the alien. The other members of the crew are killed by the alien and Ripley escapes with the ship cat (Jones). The Nostromo self-destructs but Ripley finds the alien sleeping on board the escape ship. She opens an airlock and the alien is sucked into space, but it manages to grab onto the sides of the airlock. Ripley shoots the alien with a grappling gun, knocking it free of the ship. She then activates the craft's engines and kills the alien. The movie ends with her sending out a call for help to any nearby ship before placing herself and Jones into hyper-sleep.
Space travel is extremely slow so crew members must spend time in hyper sleep for years possibly.
The Nostromo is a massive ship but it only requires the a crew of seven. The ships computer, named "Mother," runs most of the function.
- Only the actor involved and Director Ridley Scott were in on the filming of the "chest bursting scene." The director had called cut and the other actors had no idea their dialouge and reactions were being filmed. Scott did this to heighten the reality of the scene.