Other Titles: この中に1人、妹がいる！
Rate: 9.1 (Rated by 235 Members)
Aired: Jul 5, 2012 to Sep 27, 2012
The story centers around ShÅgo Mikadono, the son of an industrial magnate who passed away. As a final wish, ShÅgo's father gave him a condition before he can inherit his legacy â€” find a female mate at school. ShÅgo transfers into a school to fulfill that condition. However, ShÅgo learns that he has a sister who was separated at birth. ShÅgo does not know what his long-lost sister looks like, but she happens to be one of the students at ShÅgo's new school.