Yasuko, a single mother raising her daughter Aya in a run-down apartment, struggles to make ends meet with her job at a bento shop. In order to provide for Aya, she turns to the sex industry. One day, upon returning home, Yasuko discovers that Aya has been kidnapped. However, Yasuko chooses not to try to retrieve her daughter. Why wouldn't Yasuko, for whom Aya is everything, attempt to bring her back? From that day on, Yasuko's secret routine begins. Unbeknownst to anyone, one man watches her every move intently.