Summer 1876

A giant sea monster known as "Dragonsaurus" has emerged from out of nowhere, terrorizing the depths of the oceans. Great Mazinger, Grendizer and the Getter Robo G team join forces to combat the new threat. But their task becomes more complicated when Dragonsaurus swallows up Boss Borot and makes its way towards Tokyo.

The peace of the world is suddenly threatened by Mogool, which is located on the bottom of the sea. Helqeen, tyrannical master of the Mogoolian Empire, attempts to conquer the earth with her faithful companions Goroskie and Zan-gack. In order to frustrate their ambition, Dr. Yuri, who predicted this horrible occasion, organizes four powerful robots to form the Blocker Corps! He also gathers four members who have the super ability known as "elepath" - a talent for maneuvering gigantic robots. A fierce battle begins between our Blocker Corps and Mogool at the risk of their lives! A series of fantastic and fabulous battles unfolds.

The focus of the anime was to showcase folktales from different prefectures. Each episode was composed of two stories.