After being invited to the island of Barou, three girls learn of their missing older brother’s fate, as well as the fact that they are to inherit this island kingdom in the absence of a suitable male heir.

Upon visiting the idol of Ranga deep within the jungle, the irritated trio actually manages to awaken the sleeping giant from its dormancy. With this event in mind, it comes as no surprise to them when the lumbering behemoth Neo Ranga arrives in Tokyo months later to seek out its three lovely masters. Instead of rolling out the red carpet for their gigantic friend, the Japanese Self Defense Force rolls out the tanks and artillery to halt the behemoth’s advance through downtown Tokyo.