Yoshikawa Haruo is just your average middle school boy who doesn`t have many goals, other than to live a long life. He is the eldest of his family, and lives with his 3 younger sisters in a home with no parents. He is completely unaware of his sisters` magical powers, and supposedly has some of his own, but they have not been discovered yet. One day, a mysterious, yet beautiful, girl appears before him. This is Mamiya Ayumi, who also has magical powers. Her goal is to `make Haruo into a man` so that she can break the curse that was put on her as a young child.