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.
Elenco: Minami Takayama , Kappei Yamaguchi , Wakana Yamazaki , Akira Kamiya , Rikiya Koyama , Megumi Hayashibara , Kenichi Ogata , Ikue Otani , Wataru Takagi , Chafurin , Yukiko Iwai , Kotono Mitsuishi , Kikuko Inoue , Fumihiko Tachiki , Hideyuki Tanaka , Kenichi Ogata , Sumi Shimamoto , Unsho Ishizuka , Yukiko Iwai , Yukitoshi Hori , Yuko Miyamura , Wakana Yamazaki , Kappei Yamaguchi , Minami Takayama , Akira Kamiya , Rikiya Koyama , Ryotaro Okiayu , Ai Orikasa , Atsuko Yuya , Hiroyuki Kinoshita , Asako Dodo .