My little sister has been living naked since she was little... forbidden fantasies never end! Calligraphy girl Tsukasa is a high school student who has been living naked since she was ○ years old. Her remarried parents accept this nudist lifestyle. However, even as a step-brother, seeing his little sister's naked body every day under the same roof pushes his patience to its limit. One day, when their parents go on a trip... The homeroom teacher and nude calligraphy, his brother's friend, the clockmaker who came to deliver packages, and the brother who has gone beyond his limits.
