Case Closed, Vol. 5 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.

A vicious murderer whose face is covered in bandages is on the lose. Will Conan be able to catch him before he strikes again?

And later, Conan's friends Rachel and Serena want to blow off some steam but they get more than they bargain for when they discover murder at the karaoke box.

Can you figure out whodunnit before Conan does?