Conan and the Gang are playing hide and seek in the park when Ayumi decides to hide in the trunk of a car. The trunk is locked and the car drives off with Ayumi still inside. Luckily Hiroshi had given them communicators so they can talk to her. There are reports going around about a child killer on the loose and when she finds a bloodied up saw and a Girl's head in the trunk Conan fears for the worst. Conan and the gang chase after the car on his new solar powered skateboard.