In a remote region of the galaxy, the United States space tug, Nostromo, carrying a cargo of mineral ore, makes its return journey to Earth. The ship’s crew - five men, two women and a cat - are awakened from their hypersleep chambers when Mother, the on-board computer, monitors a strange transmission. According to Company law, the crew must investigate any signal indicating possible intelligent life. What begins as a routine search mission quickly escalates into a nightmare of unimaginable terror when the crew discovers and brings aboard an extra-terrestrial life form.