Original creator (light novel) : Hajime Taguchi
Original Character Design : CUTEG
Plot summary : The story centers around Shōgo Mikadono, the son of an industrial magnate named Kumagorō Mikadono who passed away. As a final wish, Kumagorō gave Shōgo a condition before Shōgo can inherit the family legacy — find a female mate at school. Shōgo transfers into a school to fulfill that condition. However, he learns that he has a younger sister who was separated at birth. He does not know what his long-lost sister looks like, but she happens to be one of the students at his new school.
Note : Taguchi launched the light novel series last year, and the fifth volume shipped in August. Mottun* has been adapting the light novel series into a manga (with the subtitle
Who is Imouto?) in Media Factory's Monthly Comic Alive magazine since May.