Orphaned at a young age, two sisters with no relatives are adopted by a painter. The elder sister, Tsubomi, starts working through a referral from their father, while the younger sister, Shizuku, is allowed to attend school. However, a dark secret lurks within this household. The father sexually abuses Shizuku under the guise of twisted affection, while Tsubomi remains unaware, pushing herself to the limit to avoid worrying her sister. One night, Tsubomi is shocked to witness Shizuku in a shameful, exposed state. Overcoming that moment, she resolves to protect her sister at all costs.