Seymour Krelboin (Jonathan Haze) works in the Skid Row flower shop owned by Mr. Mushnik (Mel Welles). In his spare time, Seymour creates a new plant species he names Audrey Junior in honor of his girlfriend Audrey (Jackie Joseph). Audrey Junior begins speaking and demands to be fed human blood and flesh, convincing Seymour to kill a railroad detective, a sadistic dentist and a trollop. Seymour's guilt over the deaths forces him to confront Audrey Junior in a final confrontation.