When a computer matchmaking service connects her to "Nick," a man with an astonishing secret agenda, Margo Sanchez is drawn into the most bizarre courtship of all time. Finding herself falling for Nick, she is stunned when he claims to be Santa Claus and wants to make Margo the next Mrs. C.

Disbelieving, Margo challenges Nick for proof. Abruptly, she is transported from her San Francisco home to Nick's magical realm at the top of the world. There she encounters elves hiding ancient secrets and engages in bristling debates with her suitor, while surprisingly being drawn to him and his enchanted world.

Despite Nick's gallant courtship, Margo turns him down and returns home. But shortly before Christmas, a calamity in Nick's world summons her back. There she is alarmed to learn that the crisis threatens cataclysmic global devastation—and that only Margo might be able to stop it.

Before she can act, however, the previously untold secrets of Santa's realm, its elves, and their true mission on earth must be revealed to her. These shocking realities impel her on an unprecedented odyssey—an epic round-the-world journey that provides a surprising climax to a most remarkable holiday romance.