Pete the groundhog (Buddy Hackett) narrates the tale of elfin Jack Frost (Robert Morse), whose job it is to leave frosty deposits on the windows on chilly winter days. A pretty blonde girl named Elisa lives in the small town of January Junction. Jack is smitten with Elisa and his love for her warms his heart to such an extent that he becomes a real boy. Tyrannical ruler Kubla Kraus (Paul Frees) on horseback kidnaps Elisa. Jack pleads with Old Man Winter to allow a couple of his elf friends to help him rescue Elisa from the dictator's castle. His friends tell him that the only way Jack can defeat Kubla's soldiers is to give up being a human boy. Once going back to his original form as Jack Frost, he can never again be human. To save Elisa from a life in captivity, he will have to make that sacrifice in order to liberate her.