She is a human being, but she is also the king of beasts. She knew all beasts at the age of five. She practiced secret techniques that only beasts can practice at the age of ten. She controlled all beasts and built a beast city at the age of fifteen, and became a legendary woman. He is the eldest son of the Prime Minister of Daye Kingdom. He has a noble status, but he is born with a weak constitution. He seems to be "incompetent in martial arts", but he has established a terrifying force. Daye Country specializes in killing beasts, so she and he are destined to be at odds. All of this quietly changed that summer...