Detective Nishina Sosuke, the director of the Metropolitan Police Department's Investigation Division 1, is suddenly attacked by a trio of men at his apartment at midnight. When he regains consciousness, the corpse of a foreigner shot with his pistol lies in front of him. Nishina, with the help of his friend and newspaper reporter Mineshima, who believes in his innocence and vows to cooperate, pursues the incident and reveals a conspiracy related with 5,000 kilograms of gold that disappeared at the end of the WW2.