Jack Frost (MICHAEL KEATON) is poised to achieve a lifelong dream: he's about to make it big as a musician after years of hard work. His passion, however, has a price-days and nights away from his wife Gabby (KELLY PRESTON) and son Charlie (JOSEPH CROSS).

Gabby and Charlie both love Jack, but it only makes them miss him more when he's on the road, and Charlie hates all the broken promises that come with having a dad who's hardly ever around.

Jack tries his best to make it up to his son; one evening the two of them build a snowman together after Jack's been away on the road, and Charlie is thrilled just having his dad around to share the experiences other kids take for granted. Later, Jack gives Charlie an old harmonica and tells him that it has magic powers. "Whenever you play this, no matter where I am, I can hear it," Jack promises. Both of them wish the little story were true.

One Christmas, Jack realizes with a jolt that there's nothing more meaningful to him than his family. Right then and there, he decides to skip the most important audition of his career to spend the holidays at home. But when Jack's car skids off the road, he's killed before he has a chance to make it back.

The following year, many things have changed for Charlie. Life is even tougher than it was, now that he has no dad at all. As Christmas approaches, a heavy snow falls. Longing for his father, Charlie remembers the wonderful time the two of them had building that snowman; this time, he decides to make one by himself. When his frozen creation is complete, he tops it off with his dad's old hat, scarf and gloves. Then, before he falls asleep that night, Charlie takes out the old harmonica his dad once gave him, and he plays. He remembers his father's promise: "If you play this, I will always hear you, no matter where I am." More fervently than ever before, Charlie wishes the story were more than a wistful fantasy.

And that night Charlie's wish comes true. Jack Frost comes back to Earth, but in a way that neither of them could possibly have imagined...as a snowman.