The Misaki family lives with their father, daughter and son after their mother passed away two years ago.The father works hard for the family, and the brothers and sisters look at the father's back, the daughter goes to school but does the housework instead of the mother, and her son has also started working, and the parents and children live in harmony.However, Kanna, her older sister, has secretly held feelings for her younger brother for a long time, and she spends her days masturbating and suppressing her feelings.But one day when her father is gone on a business trip, Kanna takes drastic action against her younger brother! !