Hikaru Sakimori and his family are natives of the planet Peaceland, which became under attack by the beings of a neighboring planet, Garoga. The planet was ultimately seized and destroyed, forcing the Zone Family to flee to Earth. The Garogas, wanting only for Hikaru's death, followed the family to Earth and began plotting its subjugation. Hikaru and his siblings possess the ability to transform into the superheroes known as Zone Fighter, Zone Angel, and Zone Junior. However, Hikaru is the only one of the three who is also able to grow to giant size. The Garogas often deploy giant monsters to terrorize Earth and Hikaru uses his unique ability to challenge them. By day, Hikaru is a test driver for a car manufacturer,[3] but harbors only contempt for the Garogas, battling against them to protect his new home planet.