Professor Bond is conducting research on an island in the Java Sea when his son discovers a giant ape, befriends him, and together they protect Kong from Dr. Who, who has sinister designs on the ape. Each episode follows a structure that alternates between King Kong stories and a gag cartoon titled Tom of T.H.U.M.B., featuring a secret agent and his oriental sidekick, before returning to another King Kong narrative. Animage Pocket Data Notes credit MORI Yasuji and KANISHI Takao as either character designers or animation directors for Tom of T.H.U.M.B., a role that differs from the credits for the King Kong portion. The series is notable for being the first cartoon television series animated entirely in Japan specifically for an American audience. American sources state that Rankin‑Bass commissioned the work from Videocraft International, while Japanese sources indicate it was produced by Videocraft/Toei Doga.