In the land of Ryoza, the neighboring provinces of Shin-Ou and Tai-Kou have been at peace. Queen Shinou is the ruler of Ryoza and her greatest general, Grand Duke Taikou, defends the kingdom with his army of powerful war-lizards known as the Touda. Although the two regions have enjoyed a long-standing alliance, mounting tensions threaten to spark a fierce civil war. Within Ake, a village in Tai-Kou tasked with raising the Grand Duke's army, lives Erin, a bright girl who spends her days watching the work of her mother Soyon, the village's head Touda doctor. But while under Soyon's care, a disastrous incident befalls the Grand Duke's strongest Touda, and the peace that Erin and her mother had been enjoying vanishes as Soyon is punished severely. In a desperate attempt to save her mother, Erin ends up falling in a river and is swept towards Shin-Ou. Unable to return home, Erin must learn to lead a new life with completely different people, all while hunting for the truth of both beasts and humanity itself, with tensions between the two regions constantly escalating.

Let not an Outsider touch thee, Lest thou shalt be cursed forever. Once upon a time, in a land far away that was divided into two realms... The Outside was roamed by teratomorphic creatures who had the power to curse whoever they touched. Humans could live safely only in the Inside. But when a lost little girl from the Inside named Shiva, and a demonic beast-looking Outsider simply known as Teacher initiate a quiet coexistence on the same side of the forest, their bond seems to transcend their incompatible natures. It is the beginning of a folktale about two outcasts -one human, one inhuman- who linger in the hazy twilight that separates night from day. (Source: Production I.G)

As humanity's war with the Neuroi—a mysterious, hostile alien race possessing weapons of unparalleled power—continues being fought across Europe and Africa, a new fighter squadron is formed. The 502nd Joint Fighter Wing, also known as the Brave Witches, operates on the eastern front, scouring the icy vastness of Orussia in search of alien invaders. However, one of the Brave Witches' members suffers severe injuries on her way to the squadron's headquarters, rendering her unable to participate in any operations. As a result, her sister, Hikari Karibuchi, volunteers to take her place. Though not possessing any special abilities or significant magical powers, she is determined to live up to the expectations of her new comrades and prove herself worthy of the name of a Witch.

Prequel to Burn the Witch.