Nakayama Sachi was abandoned by her mother Yumi when she was 5 years old and grew up at an orphanage. Now that she has turned 20, she works a part-time job late night at a supermarket which opens 24 hours. Besides that, drawing pictures is her only emotional refuge. One day, Sachi is accosted by one of the supermarket's regular customers, Mayu, a 17-year-old girl who has runaway from home. On the first day of their meeting, Mayu comes to live at Sachi's apartment, and like a stray cat, she ends up staying. Mayu is cheerful but there is something fragile about her, and Sachi cannot thrust her away. A couple of days later, Sachi hears from her uncle, Nakayama Naoyuki, that he has found her mother.