Ghastly beheadings, bloody murders, and coldhearted child abductions! Precocious high school student Jimmy Kudo uses his keen powers of observation and astute intuition to solve mysteries that have left law enforcement officials baffled. Hot on the trail of a suspect, Jimmy is accosted from behind and fed a strange chemical which physically transforms him into a grade schooler! Taking on the pseudonym Conan Edogawa, he attempts to track down the people who did this to him. But until he finds a cure for his bizarre condition, Jimmy continues to help the police solve their toughest cases.
Yutaka Takai is a brilliant 15 year old high school inventor who is tired of being referred to as young and small. His older girlfriend, Mamiko Abe, attempts to cheer him up but with no luck. Yutaka requests for Mamiko to meet him on top of the school one night and shows off a jet pack he had demonstrated earlier at school that day. Yutaka explains that it is not just a jet pack, but a time machine as well. Yutaka wants to travel in time to where he's better suited for Mamiko and not young or small. While Yutaka isn't paying attention, Mamiko takes the time machine and uses it on herself, jumping off the school building and telling Yutaka to "Wait for me". Yutaka is dismayed by Mamiko's disappearance and frightened when he discovers everyone in town is beginning to forget Mamiko ever existed.