Chief Inspector Kiyonaga Matsumoto once hunted a dangerous serial killer in his youth. Now, just a few days remain until the statute of limitations expires on this series of murders, when suddenly a suspect appears! A clue to the perpetrator from back then is the Beatles classic "Let it be," which the killer used to whistle. But what incredible truth really lies behind this case? Additionally, there are still cases involving a mackerel, a carp, a sea bream, and a turbot, as well as the beginning of a new showdown with Kaito Kid for Conan and his friends!.