Misao Harada has seen demons since childhood and holds vague memories of a boy who shielded her from these troublesome creatures, promising to return for her someday. Now a high school student, Misao longs to be normal and have a boyfriend. One day, as she heads home, she spots a handsome stranger who has moved in next door. To her surprise, he introduces himself as Kyou, her long-lost childhood friend and first love. The following day, on her 16th birthday, Misao is suddenly injured by a classmate. Revealed to be a demon, he intends to eat her to gain eternal youth. When all hope seems lost, Kyou rescues her, revealing himself as the leader of a Tengu clan. Since taking Misao as his bride will bring prosperity to his clan, he presents her with a choice: sleep with him and become his bride, or face further attacks from other demons attracted to the power of her blood.