"Don't Call Me Daddy"

Yuuta Segawa starts his first year in college. After three months, he becomes acquainted to Kouichi Nimura, Raika Oda and Shuntarou Sako who are part of the Street Observation Research Society club. On the request of his older sister, Yuri Takanashi, Yuuta visits her family and is introduced to her daughters, Hina, Miu, and Sora who happens to be undressed at the time.