The film tells the story of Willy McBean, a young schoolboy who teams up with an anthropomorphic monkey named Pablo to prevent the villainous professor Rasputin Von Rotten from changing the history of the world, using the newly created and duplicated "magic" time machine.

Written, produced and directed by Arthur Rankin, Jr., with Jules Bass and Larry Roemer as associate producers, the film uses a team of voice actors under the soundtrack recording supervision of Bernard Cowan in Canada, including Larry D. Mann as Von Rotten, Billie Mae Richards as Willy And Paul Soles as Pablo the Monkey.

Tadahito Mochinaga supervises the "Animagic" stop motion process at MOM Productions in Japan, the same team behind the animation for The New Adventures of Pinocchio (1960–61) and Rudolph the Red-Nosed Reindeer (1964).

A talking green dragon then crashes into Camelot in an effort to eat everyone, but King Arthur and Excalibur are able to drive him away.

After a quick diversion to the Roman Colosseum, Willy and Pablo later go to Ancient Egypt to stop Von Rotten from building the Great Pyramid.