After solving a party guest's murder, teenage detective Jimmy Kudo and his friend Rachel Moore relax at an amusement park, where another death occurs and Jimmy must deduce the culprit once again; suspicious men drug Jimmy after they catch him spying.

The poison meant to kill Jimmy instead transforms him into a young boy, and he finds Professor Agasa to find out what happened to him; they devise a new identity to protect Jimmy from further attempts on his life, creating the guise of Conan Edogawa.

The professor develops a bow tie that can change Conan's voice; Conan meets the students at his new school; a singer asks Detective Richard Moore to help her with a stalker, but when a man's body turns up in her home, Richard suspects her of murder.

A treasure map intrigues Conan and his friends, but they unknowingly follow the clues into danger.

Thinking he recognises the men from the night he was drugged, Conan eavesdrops on two men wearing black while riding a bullet train and hears about a bomb on board.

When Rachel and Serena attend a Valentine's Day dinner party with some boys, they learn that murder is on the menu.