Kyoji Kobayashi

Banished from the peaceful simian Planet E, the mad scientist Dr. Gori and his brutish assistant Karras (Lla in the Japanese version, as in "gorilla") search for a new planet to rule after Gori's plot to conquer Planet E had been foiled by its government. (tvtropes.org)

Osamu Tezuka is going to a 21st Century new year's party with all the characters he made. One thing leads to another and he ends up missing! It's up to his most popular characters to find out what happened to him and get him back safely before the rest of the guests show up.