An old man known as a mining king was found killed by a “golden bullet”. The first to be suspected was the phantom thief at large known as the Benevolent Picaroon, widely talked about around town. But Inomata, the private eye investigating the case, didn’t think the killing-averse outlaw was behind the murder. A few days later, a note from the Picaroon was found at the crime scene of another wealthy household. Rushing over, Inomata finds something dubious about the behavior of the tycoon’s daughter. He calls in his buddy detective Kawanami and launches a serious probe to find out the truth. Whatever happened to the “golden bullet” — the key to the case? And who in fact is the Benevolent Picaroon?

Two outsiders start a relationship in a mining town.