The premise of Gransazer is unique compared to other superhero shows. The story reveals that millions of years ago, an ancient civilization on Earth was destroyed by an alien force. In the present day, 12 descendants of this civilization are chosen to protect the planet.

Chouseishin Gransazer (often just called Gransazer ) was the first installment in Toho Company's "Chouseishin Series." It premiered in Japan in 2003 and soon found its way to Indian television screens via channels like Jetix and later Disney XD.