Chuya (Mitsuru Matsuoka) works as a university professor. His big dream is to make a sound map of Tokyo. He spends his days collecting sounds in Tokyo and analyzing the sounds. One day, his girlfriend Fumi (Natsumi Abe) tells him that she is leaving him and mysterious woman Mariko (Yumi Adachi) appears in front of him. Mariko, who knows about the break up of Chuya and Fumi, suggests to Chuya to wiretap Mariko’s life.

Elementary student Tanabe Kento is struggling to draw a map of his town for his summer vacation homework. One day, a fracas occurs involving a mysterious man, junkman. After that, Kento discovers a Hiroshima that he'd never known, and decides to draw a map of his very own.

A man known as the "Murderer" wanders through the woods. The sound of water flowing deep underground fills his head...