The story begins with high-school student Yachi Haruaki receiving a mysterious package, a super-heavy black cube from his father overseas. That night, Haruaki wakes to a suspicious noise in the kitchen and discovers a cute-looking stark-naked female thieving rice crackers. After the embarrassing moment, the girl presents herself. Her name is Fear (pronounced "Fia" in Japanese), and is the first of several surprises that Haruaki is to receive.