Supergirl was released in 1984, shortly after the third Superman movie.  Kara-El is the cousin of Superman who is searching for the power source Omegahedron desperately needed by survivors of the planet Krypton.  Her search for it leads her to Earth, where she becomes just as powerful as her cousin.  However, she encounters unexpected obstacles and dangerous battles when a woman who practices the occult takes Kara-El’s powers from her and uses it to cause mayhem and destruction.  To get her powers and Omegahedron back, Kara-El has to battle the forces of Black Magic, among which is a hundred-foot tall monster made entirely out of pure energy.