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. To do so, she is forced to work as a maid in their house. She's adored by all the boys in school, but hated by Kurusou Yuri, the serious, driven, and orderly class president who has had a crush on Haruho since they were young...
