In space no one can hear you scream. Alien is the first movie of one of the most popular sagas in science fiction history and introduces Sigourney Weaver as Ripley the iron-willed woman destined to battle the galaxy's ultimate creature. The terror begins when the crew of the spaceship Nostromo investigates a transmission from a desolate planet and makes a horrifying discovery a life form that breeds within a human host. Now the crew must fight not only for its own survival but for the survival of all mankind.