Jimmy Kudo, the son of a world-renowned mystery writer, is a high school detective who has cracked the most baffling of cases. One day while on a date with his childhood friend Rachel Moore, Jimmy observes a pair of men in black involved in some shady business. The men capture Jimmy and give him a poisonous substance to rub out their witness. But instead of killing him, it turns him into a little kid! Jimmy takes on the pseudonym Conan Edogawa and continues to solve all the difficult cases that come his way. All the while, he's looking for the men in black and the mysterious organization they're with in order to find a cure for his miniature malady.

Conan is baffled by a murder at a snowbound mansion--and with stage magicians for suspects, anything seems possible. Is this really a case of murder by magic? As the mini-detective tries to conjure up a solution, he doesn't suspect that he's about to cross paths with an old nemesis! Then Detective Moore's dream comes true: he's going to see his favorite singer, Yoko Okino, in concert! But he's forced to cancel his big night out when a girl dies in a locked bathroom. Is it a case of suicide...or revenge?