Fairies possess and reside within animals, granting them special powers. By surgically removing and transplanting the organs of a possessed animal into a human, humans can partially summon the fairy and use it as a weapon. Eventually, such individuals were used for war, and were called Fairy Soldiers. After a long war, these soldiers lost their purpose, and had to reintegrate into society. Nine years after the end of the war, Maria is a fresh recruit of Dorothea, an organization dedicated to the investigation and suppression of fairy-related crimes and incidents. Even in peacetime, the government is still unstable after the war. Many criminals still have lingering wounds from the previous conflict, and there are terrorist groups bent on revenge.