Case Closed, Vol. 4 by Gosho Aoyama

Can Detective Conan crack the case…while trapped in a kid’s body?

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.

Bloody murder is committed at a museum, reproducing a scene from a gruesome painting.

Later, the men in black are back! Will Conan be able to come any closer to getting his old body back?

Also, Conan's friends from grade school find a treasure map--but will it only lead them to a trove of trouble?