Conan Edogawa and his classmates are assigned to do a class report about a small business of their choice. After discarding other possible topics, the Detective Boys concludes that it's a perfect opportunity to find out more about Detective Kogorou Mouri's job. Conan's friends refuse to settle for a simple interview though, as they want to experience first-hand all the details of his work. Thus, they, along with a reluctant Conan and Ai Haibara, decide to tail the renowned detective for a day. However, the kids soon get involved in a grim situation when Kogorou's current case takes an unexpected and dangerous turn.

Once again, Kaitou Kid has a target in mind: the Crystal Mother, Europe's largest topaz owned by Queen Selizabeth of the Principality of Ingram. He intends to steal this jewel while the Queen is stuck on a train from Tokyo to Osaka. However, Kid's abilities are put to the test, as the Queen has already concealed the gem somewhere aboard the train. Conan Edogawa, who is among train's passengers, suspects an attack from the phantom thief and begins investigating on his own, while Inspector Ginzou Nakamori is ready for a new confrontation against the elusive jewelry robber.

Conan and Ran are visiting Heiji and Kazuha in Osaka when the four come across a trio of kids while touring the city. These children, who look eerily similar to the Detective Boys but with different personalities, are looking for their friend who has gone missing—and the two young detectives agree to help find the vanished boy.

Conan Edogawa and the rest of the gang are invited to Inspector Ninzaburou Shiratori's villa for a small gathering. The party's highlight is Shiratori's prized wine collection—including his most expensive vintage—and a bottle from it will be served for the evening. However, just as this wine is to be brought out, Shiratori finds the bottle smashed on the floor—and the culprit can only be among the 16 people present in the gathering.