Detective Kozo

The Black Heart Gang robbed the National Bank of Japan, and one of the gang members was caught by the police. However, the culprit was poisoned to death in the detention center to silence him. Daimaru, a reporter in the social affairs department of the Toyo Shimbun, wrote an exclusive article about the incident, but the next day's morning edition carried a small article saying that the culprit had committed suicide. It was the department chief and reporter Hiruta who changed the article to say that the culprit had committed suicide. By chance, Daimaru overheard a secret conversation between the two and discovered the truth...!?