I hear my sister scolding my brother. It is a regular morning event at the Utsumi household. The brother who is being scolded, Utsumi Mitsuru, was troubled because he couldn't get along with his adopted sister, Miyu. The underdeveloped body, represented by her short hair, doll-like sharp features, and flat chest, was the ideal image of a sister for Mitsuru. Although he fantasized about sweet days with his adopted sister, Miyu only acted spoiled in front of their parents, treating him like garbage when they were alone. One day, as he was enduring his difficult days as a brother, he found out that Miyu had a complex about her chest.
