After losing her mother, Yukine Sakuragi had been living away from her family home. She finally decides to return to the household where her stepfather and younger brother reside. Reuniting with her brother brings her comfort, but everything changes when she uncovers a dark secret about her stepfather and brother. She learns that her stepfather is bisexual and has been using her younger brother for sexual relief. Feeling responsible, Yukine resolves to step up as an older sister and take matters into her own hands. A poignant yet tender story depicting family bonds and inner conflict.