Supergirl (1984)

Kara Zor-El lives in an isolated Kryptonian community named Argo City, in a pocket of trans-dimensional space. A man named Zaltar shows Kara the unique and immensely powerful Omegahedron, which he has borrowed without the knowledge of the government, and powers the city; however, after a mishap, it is blown out into space. In an effort to recover it and save Argo City, Kara follows it to Earth, where it has fallen into the hands of the would-be witch Selena.