The Fiend with Twenty Faces

When 1930s Tokyo is threatened by a master thief who claims he can take on any disguise and stymie any matter of law enforcement, the people of the city have nowhere else to turn but Japan's greatest detective, Akechi Kogorō. Unfortunately for Tokyo, however, Akechi Kogorō is off on overseas business, so it becomes the job of his 12-year old assistant, Kobayashi Yoshio, to track down the thief and desperately keep him at bay until his mentor returns.