Kono Naka ni Hitori, Imouto ga Iru!

Preparing to inherit his family's business brings Shogo Mikadono an unusual condition: his mother expects him to find a suitable future wife while he is still at school. At his new academy, meeting potential partners soon proves much easier than understanding their intentions.

News of a sister he has never known makes that search considerably more complicated. She may be among the girls drawing close to him, so Shogo must establish her identity before pursuing a relationship. Family expectations and an increasingly tangled set of clues leave him questioning encounters that initially seemed promising.