The story centers around Shōgo Mikadono, the son of an industrial magnate who passed away. As a final wish, Shōgo's father gave him a condition before he can inherit his legacy — find a female mate at school. Shōgo transfers into a school to fulfill that condition. However, Shōgo learns that he has a sister who was separated at birth. Shōgo does not know what his long-lost sister looks like, but she happens to be one of the students at Shōgo's new school.