Murakami (Toshiro Mifune), a young detective investigating a series of murders, loses his service weapon one day. Ashamed of his mistake, he rushes to find it, but to no avail. Meanwhile, as the detective searches for his gun, the stolen service weapon has already become a murder weapon. Murakami then enlists the help of Sato (Takashi Shimura), an experienced detective with the Tokyo Police Department. Will they manage to find the criminal?