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 no great surprise to find a corpse in Kashiragami Forest--the supposedly cursed forest is a popular destination for would-be suicides. But the latest suicide case has the local police suspecting foul play. Then a tall, dark man with a moustache hangs himself at a local hotel...after claiming to be Detective Moore Are the suicides really something more sinister...and is the killer laying a trap for Conan and the real Detective Moore?