When the Dunbas Empire threatens the peaceful realm of Rimbell, three princesses vow to defend their land, with the spirited and sword-wielding Luna leading the charge. In a magical twist of fate within the castle's cellars, Luna becomes fused with the colossal green reptile Varga, serving as its guiding force while sporting a reptilian tail even in her human guise. Tasked with repelling a relentless giant invader and saving her abducted sister from a menacing pterodactyl, Luna's bravery and unique bond with Varga are put to the ultimate test.