Seymour Krelborn is a nerdy orphan working at Mushnik's, a flower shop in urban Skid Row. He harbors a crush on fellow co-worker Audrey Fulquard, and is berated by Mr. Mushnik daily. One day Seymour finds a very mysterious unidentified plant which he calls Audrey II. The plant seems to have a craving for blood and soon begins to sing for his supper.

Plagues are ravaging Thebes, and the blind fortune-teller Tieresias tells Oedipus, the King, that the gods are unhappy. The murder of the former king has gone unavenged, and Oedipus sets out to find the killer.