In the peaceful realm of Ryoza, Queen Shinou reigns over the lands of Shin-Ou and Tai-Kou. Grand Duke Taikou, her trusted general, commands an army of fearsome war-lizards called the 'Touda' to safeguard the kingdom. Despite the longstanding harmony between the provinces, rising conflicts threaten to shatter the tranquility. Within the village of Ake in Tai-Kou resides Erin, a curious girl who observes her mother Soyon, the village's skilled Touda healer. A tragic event involving the Grand Duke's prized Touda disrupts their serene existence, leading to Soyon's harsh punishment. In a twist of fate, Erin is swept away to Shin-Ou while trying to rescue her mother. Cut off from her past, Erin must adapt to a new life surrounded by unfamiliar faces, all while delving into the mysteries of creatures and humanity itself. As tensions between Shin-Ou and Tai-Kou escalate, Erin's quest for truth becomes intertwined with the fate of both realms.