The story is narrated by a groundhog named Pardon-Me-Pete, who has a deal with Jack Frost to extend winter by 6 weeks, letting him sleep that much longer. Pete starts to talk about the legend of Jack Frost. It all starts when Jack Frost, an immortal winter sprite, falls in love with a human girl named Elisa, who proclaims her love for Jack after he rescues her when Kubla Kraus, an evil Cossack king who lives all alone in his castle on Miserable Mountain, except for his iron horse Klangstomper, his clockwork butler Fetch-Kvetch, his army of Keh-Nights, and a ventriloquist's dummy named Dommy as his sidekick, all made of iron since no people or animals could stand to live with him due to his arrogance and greed, cracks the ice she is standing on. Jack asks Father Winter if he can become human in order to be with her. Father Winter gives him a chance but warns that Jack must prove he can succeed as a human, by earning a house, a horse, a bag of gold, and a wife by the first sign of spring. Jack agrees and turns human, assuming the identity of Jack Snip. He runs a tailor shop in the town of January Junction with two friends who also turned human, Snip the snowflake maker and Holly the snow gypsy. Snip and Holly were sent by Father Winter to ensure Jack does not get into trouble. Elisa is charmed by "Jack Snip", but she harbors romantic dreams of Sir Ravenal Rightfellow, a "knight in golden armor". Elisa is soon kidnapped by Kraus and taken to his castle. Kraus also possesses all the brick, gold, and timber that January Junction used to have. After Elisa is rescued by Sir Ravenal, Kraus vows to destroy January Junction by sending one-thousand Keh-Nights in an attempt to recapture his bride and throws Jack, Snip, and Holly in the dungeon. Jack gives up his humanity in order to whip up the biggest blizzard ever, freezing Kraus and his 1,000 Keh-Nights in the castle. Snip and Holly change back to sprites as well. This tactic works until Groundhog Day arrives. As the sky is overcast with no sun to cast shadows, Jack Frost uses his magic shadow to scare Pete back into hibernation, and continues whipping up the storm. Finally, with only 1 hour left before the arrival of spring, Jack returns to human form to stop Kraus by tricking his Keh-Nights into walking off the icy mountain to their destruction by imitating Dommy. Afterward, Jack causes Kraus to fall out of his castle and Father Winter literally blows him far away from Miserable Mountain, leaving Jack to claim the gold for himself; tames Klangstomper, making him his horse; and the castle becomes his house. He races off to ask Elisa's parents for her hand in marriage, but during his absence, she has fallen in love with Sir Ravenal, and he with her. Jack becomes a spirit again for good, and blows ice onto Elisa's wedding bouquet, turning it white. When asked about the change, she sheds a tear saying "An old friend just kissed the bride." Snip calls out to Jack that winter wouldn't be the same without him. Before heading back to sleep, Pete says that Jack Frost still plays his tricks on him to ensure that there are 6 more weeks of winter, but he doesn't mind because he enjoys the extra sleep.
The licensing for Jack Frost was relatively lax for many years and as early as the early 1990s, independent discount home video distributors produced VHS copies from 16 mm prints. The special did not, as occasionally stated, lapse into the public domain; the Copyright Act of 1976 had taken effect by the time the special was published, which granted Rankin/Bass and its successors automatic copyrights of 75 years, and the program had a valid copyright notice to begin with. In the fall of 2008, Warner Bros. via Warner Home Video re-released the special as an "official version" on DVD, using a digitally remastered 35 mm print as the master.
