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.

It's Conan versus the Phantom Thief! Who is this mysterious masked man? And why does he know Conan's true identity?

Later, an investigation of an extramarital affair leads to bloody murder! Also, Conan's elementary school friends decide to become super sleuths when they form the Junior Detective League! But will they get into more trouble than they can handle?

Can you figure out whodunit before Conan does?