In Italy, the international numbering for Detective Conan differs from the original Japanese broadcast. Depending on the version you are watching, these episodes cover two major, high-stakes cases:
A new girl named Ai Haibara joins Conan's class. She eventually reveals her true identity as Shiho Miyano (codenamed Sherry ), the scientist who created the APTX 4869 poison that shrunk Shinichi.
Knowing this will help me give you more specific details about the culprit or the clues! Detective Conan Rewatch: Episode 136-137
Dr. Agasa takes the Junior Detective League camping, but they get lost and seek shelter in a massive, eerie blue castle.
Conan disappears early in the episode after finding a secret passage, leaving Ai Haibara and the other children to solve the mystery of the castle's hidden treasure and a series of disappearances.
If you are following the Japanese numbering (which some Italian streaming platforms or fan-lists use), cover a fan-favorite "survival" mystery.