Set in 1930s Tokyo, the story revolves around a master thief who uses disguises to evade capture, leaving the city in turmoil. With the renowned detective Akechi Kogoro away on business, his young assistant, 12-year-old Kobayashi Yoshio, must step up to the challenge. Tasked with tracking down the elusive criminal, Yoshio faces the daunting responsibility of protecting the city until his mentor can return to restore order.
3.7