Masako and Sana go with Mitsuko and Chiseko to Matsuda's kobudo care class, where they meet Tatsu Yamaki, a delivery man who comes to deliver their box lunches. Chiseko tells Masako that he has a criminal record and is suspected of being the culprit in a series of pickpocketing burglaries that are now taking place in the neighborhood. Even at work, Yamaki is shunned by his peers because of his criminal record. At last, the burglary turns into a murder case. Masako and her friends think that they can't count on the police, so they start their own investigation to protect themselves.