Ichiban Chikakute, Tooi Futari(2008)

Ichiban Chikakute, Tooi Futari

When she was little, Ai met her newly adopted sister. When they are older, both have important jobs at school - Ai is a member of the school disciplinary committe, while the other one is a school doctor, who likes to "play" with female students. Is Ai scolding her sister because of school rules, or maybe..?