On this day, Conan, Xiaolan and his group came to the City Hall of Beika City, where a press conference for the latest game "Cocoon" was being held. Because "Cocoon", which is very different from any previous game, may change the values of the global game industry in one fell swoop, the press conference attracted people from the political, financial and entertainment circles representing the upper class of Japan. Most of the 50 game experiencers were their descendants. Shinichi's father, mystery novel master Kudo Yusaku, also came to the scene because he participated in the story writing. While it was lively here, the developer and person in charge of the game, Jiancun, was killed in the basement. The blood stains left on the keyboard J, T, and R before Jiancun's death made Conan think that the answer might be in the game. He used Yusaku's relationship to join the experiencer team, and Xiaolan, Huiyuan Ai and others also got the experience tickets. As soon as 50 participants entered a "large capsule" shaped like a cocoon, the game was controlled by an artificial intelligence called "Noah's Ark". "Noah's Ark" said that the game would provide 5 completely real historical scenes. Participants could choose one of them to enter. Those who were eliminated would enter a dormant state. If no one reached the end, their brain tissue would be destroyed. This move was to regenerate Japanese society. Conan and his group and several arrogant and rude upper-class young men entered Baker Street in London in the 19th century, where the murderer Jack the Ripper was making trouble. He had the answer that Conan was looking for! Yusaku was also investigating the case in reality.