One day, college student Miyu is informed by her mother that she has an illegitimate half-brother. Miyu's father, who divorced when she was young, remarried but disappeared after the birth of his new wife. Recently, her father also passed away, and it was decided that she would take in and raise her brother, who had no relatives. So, her brother Yuya comes to live with her, but perhaps because he grew up in a male-only household, he struggles to adapt to the new environment. Unable to watch him suffer, Miyu gently tries to comfort him by letting him touch her chest to boost his spirits.
