Supergirl is a 1984 British superhero film directed by Jeannot Szwarc. It is based on the DC Comics character of the same name and is a spin-off to Alexander and Ilya Salkind's Superman film series. The film stars Faye Dunaway, Helen Slater as Supergirl, and Peter O'Toole, with Marc McClure reprising his role as Jimmy Olsen from the Superman films. He was the only actor to do so. Kara Zor-El (Helen Slater) lives in an isolated Kryptonian community called Argo City, in a pocket of trans-dimensional space. A man named Zaltar (Peter O'Toole) allows Kara to see a unique and immensely powerful item known as the Omegahedron, which he has borrowed without the knowledge of the city government, and which powers the city. However, after a mishap, the Omegahedron is blown out into space. Much to the distress of her parents (Simon Ward and Mia Farrow), Kara follows it to Earth (undergoing a transformation into "Supergirl" in the process) in an effort to recover it and save the city. On Earth, the Omegahedron is recovered by Selena (Faye Dunaway), a power-hungry would-be witch assisted by the feckless Bianca (Brenda Vaccaro) and seeking to free herself from her relationship with warlock Nigel (Peter Cook).