After cutting herself on the sword that beheaded the original Medusa, Gloria Merrick is transformed into Medusa. Medusa's sisters Stheno and Euryale (whom are also hideous Gorgon creatures) are none too pleased that Gloria is masquerading as their dearly departed sister and they want to see her dead. Can Gloria survive Medusa's sisters? Will Stheno and Euryale come to see that Gloria is carrying on Medusa's work?