Seymour Krelborn (Rick Moranis), a shy young man working for a tyrannical florist, finds a vehicle for private and public success in the form of a man-eating plant from outer space. The carniverous shrub helps him to become a celebrity, gets rid of his boss and clears the way for him to woo Audrey (Ellen Greene), the girl of his dreams.

However, the plant's cannibalistic eating habits become insatiable and it's up to Seymour to cut it down to size...