High school teacher Chihiro hears rumors that her colleague Naoko is working as a soapland prostitute and heads to the red-light district to verify the truth. By chance, she encounters Naoko and, upon learning the details, discovers her colleague's suffering and desperate circumstances. Chihiro forces Naoko to swear secrecy, but the next day, Naoko is abruptly fired from her teaching position. Shocked by the incident, Chihiro is forced to confront the consequences of her actions, the impact on Naoko's life, and her own moral standing.