In the snowy mountains, a childless couple wished upon a star. But that star was Galeon, a mechanical lion who gifts them a baby named Mamoru. Years later, Mamoru faces an attack by the alien Zonders and is saved by cyborg hero Gai, sent by the alien defense force “GGG.” This inspires him to join GGG. Now, he works alongside Gai and Galeon who fuse together to form the king of robots: GaoGaiGar!