Betrayal degrades a person's sense of loyalty into evil. On a rainy day, a young girl is kidnapped, leading to a strangulation case where an umbrella and rain boots go missing. The police, struggling to find evidence that connects to the perpetrator due to the unusual nature of the case, request the assistance of Kuroko. However, as if mocking the police investigation, young girls are kidnapped one after another and brutally strangled. The perpetrator eventually reaches one particular young girl... Meanwhile, Kuroko gets closer to the culprit through the evidence left at the scene, but the time limit for the young girl's survival is rapidly approaching.