When clumsy Seymour Krelborn spoils two of a client's flowers, his boss Gravis Mushnick is ready to fire him from his flower shop until Seymour says he has mixed two different breeds of plant at home to create the "Audrey Jr." hybrid. Mushnick agrees to give Seymour another chance, and the next day Seymour brings in Audrey Jr., which becomes Mushnick's pride and joy and draws interest from his other employee Audrey Fulquard and more and more of their clients. Suddenly the plant ails, and Seymour accidentally learns that she likes blood. Upset because he doesn't know how to feed her, he walks along the railroad track and throws a stone that accidentally hits the head of a man who falls on the track and a train runs over him. Seymour takes pieces of the body back to the shop and discovers that the plant likes human flesh. The next morning, Audrey Jr. has grown and become the attraction of the shop. But how will Seymour feed his plant again?