While at the mythical village of Izumo Conan, Kogoro, and Ran meet a woman about to marry a terrible businessman. The businessman turns up dead and she, among her childhood friend are suspects!

The Detective Boys are at Agasa's house when they happen to find a letter from Agasa's first love. Apparently they are supposed to meet every decade but was unable to because Agasa could not solve the code from the letter. The Detective Boys set out to solve it and find the "memorable place" using the hint given in the letter. The clues lead them to the zoo where Agasa see's a brown hair women.