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 isn't sure whether to trust Jodie Saintemillion, the American high school teacher whose ditzy blonde exterior conceals a calculating mind. When a bus is hijacked by desperate criminals, Ms. Saintemillion turns out to be cannier than Conan ever imagined, revealing a head for crime solving and a body for kicking butt. But Anita can't help noticing that wherever Conan's beautiful, mysterious new ally goes, the Syndicate never seems to be far behind...