Zen Seizaki, a prosecutor at the Tokyo District Prosecutor's Office, is investigating an illegal clinical trial involving a pharmaceutical company and a university. During the investigation, he discovers a file hidden by anesthesiologist Shin Inaba. Inside the file, there are hair mixed with blood, skin, and a piece of paper with the letter F written on it. As the investigation unfolds, Seizaki realizes that there is a scheme connected to a major election within the events.