 While returning from a deep-space mission, the crew of the commercial spaceship Nostromo is awakened by a supposed SOS call from a system they are passing through. Descending to the planet s surface, they discover a strange derelict spaceship - the apparent source of the transmission - and one of the crew descends into the hold. What he finds are thousands of strange alien eggs. While examining one of the eggs, it hatches and the parasite inside attacks him. After returning to the Nostromo the crew takes off again to head for Earth. The alien parasite subsequently dies and all seems well again. But what no one knows is that another alien is quietly forming within its host - and when it emerges, the crew finds itself in serious trouble...