Kanojo ga Onii-chan ni Nattara Shitai 10 no Koto

Nanase moves into a share house when she enters high school. The house has a special rule where each resident is assigned a family role!

Father: Maki (female cop, 20 years old)
Mother: Tsugumi (female elementary school student, 10 years old)
Brother: Nanase (female high school student, 15 years old)
Sister: Karin (female junior high school student, 13 years old)

What will happen with Nanase's life with these people...!

(Source: Comic Fuz, translated)