When ace high school detective Jimmy Kudo is fed a mysterious substance by a pair of nefarious men in black--poof! He is physically transformed into a first grader. Until Jimmy can find a cure for his miniature malady, he takes on the pseudonym Conan Edogawa and continues to solve all the cases that come his way.

A man is murdered in a dockside warehouse, and the suspects are his three long-lost brothers! Conan and Harley are on the case, but scheming rich girl Momiji plans to use this test of deductive talent to further her own ends.

Then Conan helps Master Haneda solve a murder among his shogi students. And Rachel, Serena, and Sera attend a birthday party that turns less than happy when a man is poisoned right at their table!