Ishikawa, a newspaper journalist, unexpectedly meets Asako, a woman who used to work for his company some time ago as a phone operator. Three years ago, she accidentally heard the voice of a suspect who committed a still-unresolved homicide. Since then, the suspect's voice has remained lodged in her mind as a terrifying memory. One night, her husband invites over his colleagues, Kawai, Hamazaki, and Muraoka. She realizes that Hamazaki's voice sounds exactly the same as the unseen suspect's! A few days later, Hamazaki is found dead in a rain-soaked coalfield; her husband is kept in police custody as the primary suspect. Ishikawa tries to help Asako and launches his own investigation. However, the investigation soon runs into difficulty as both Kawai and Muraoka had alibis. To make matters worse, her husband implausibly confesses—Nikkatsu