Adventure starring Helen Slater. On a desperate mission to save Planet Earth, Supergirl (Slater), must retrieve a missing life-giving power source to save her home city from total destruction. Startled by her own amazing Superpowers, Supergirl traces the lost Omegahedron only to discover that it has fallen into the hands of the rapacious Selena (Faye Dunaway) who unleashes untold horrors to thwart her young adversary.