The struggle of a rookie detective, portrayed with a cheerful and comical touch. Takeshi Hayano originally belonged to the Traffic Division but was transferred to the First Investigative Division of Daimon Police Station as a rookie detective. His first case is a drug-related murder, during which he ends up missing a "key witness" pursued by his senior colleagues in the First Investigative Division. Feeling responsible, Hayano becomes depressed. Investigations, daily life, and relationships. Each episode features a variety of cases, including robbery, arson, disguise, kidnapping, fraud, and split personalities. Hayano investigates the cases together with his senior colleagues in the First Investigative Division (Chief Ushiota, Chief Detective Sugaya, Detective Yazu, Detective Maehara, Detective Hazama, etc.).