Just before Christmas, Nick Snowden, the son of Santa Claus, is balancing the heavy responsibilities of delivering gifts and upholding long-standing traditions with a desire for a quiet holiday alongside Sandy Brooks. This year, however, plans are upended during reindeer training when the team becomes too rotund to fly, leaving Nick to improvise a way to keep the festive schedule intact and, perhaps unintentionally, to blame Sandy for overfeeding the reindeer.
A heated disagreement leads Nick to grab his magical mirror, and a sudden, rough landing drops him into a garage where he loses consciousness. He awakens in a hospital with no memory of who he is or what he does, effectively forgetting that he is Santa Claus. The news of a man without memory spreads, and Sandy learns of the plight on television. Desperate to reach him, she studies Santa’s book and learns from Galfired, the book’s guardian, that she must not force the truth on Nick or risk erasing his memories entirely. With this sobering insight, she sets out on a mission to guide him back to himself, even as the mirror remains a dangerous gateway.
Nick’s path back home is complicated by Buck Seger, a longtime foe who seizes the opportunity presented by the headlines to abduct the memory-impaired Santa in an attempt to keep his amnesia intact. Buck hurries away with a train ticket to Bolivia, slipping through the crowd with little trouble until Nick, who has dozed off, misses the fastest escape. A chance encounter introduces Nick to Ryan, an orphan boy with a knack for getting into trouble. Ryan, a quick-witted pickpocket, offers to help, seeing in Nick a potential ally for his own schemes as police chase unfold. Their uneasy alliance leads Nick into an old, empty club where the atmosphere shifts from eerie quiet to a kind of old-world intrigue.
There, Henry Mays awaits, an elderly man who claims this club once belonged to him and hints at a secret society tied to Nick’s past. Henry’s presence stirs something in Nick, and soon, Sandy locates Buddy the reindeer following the mirror’s trail. Although Nick does not yet recognize her, the two soon become part of a larger plan spurred by Henry’s clues. To move forward, the group makes a bold choice: they abduct Henry from his own family to use him as a guide for staging the Christmas party within the club’s walls. Meanwhile, Ryan assists in gathering a tree and decorating it, secretly hoping the festive event will become a stage for his own budding mischief.
As the plan unfolds, Buck tracks Nick to the North Pole through the mirror and discovers the reindeer stable and Santa’s bag of wishes. Buck’s schemes intensify as he seizes the money-laden bag, which he plans to use for a quick, selfish windfall. With Christmas Eve looming, Sandy redoubles her efforts to awaken Nick’s memory. She explains how they reached this point after their quarrel, urging him to touch a mirror again. The magic, at first, falters, and Nick wanders away, leaving Sandy vulnerable to Buck’s nefarious grab.
In a dramatic turn, Nick’s memory begins to flicker back when Ryan reassures him that believing in the mirror can indeed unlock the past. The four—Nick, Sandy, Henry, and Ryan—venture through the portal to the North Pole, where Buddy helps them confront Buck and rescue Sandy from her capture. The struggle culminates in a heroic push that sends Buck through the mirror and, once again, into the garage where his memory is lost in the process.
Back on Earth, Nick and Sandy return to Henry and Ryan as a mysterious, revelatory moment appears: Nick’s parents step through the mirror and propose that Christmas be celebrated there each year. The reunion brings everyone together for a warm, hopeful celebration. Henry looks to the future and offers to take Ryan under his wing, while Nick and Sandy prepare to share gifts with those they encounter, their sleigh ride becoming a symbol of renewed family and tradition. In a final, tender note, Sandy reveals a tiny Santa suit and hints at the possibility of starting a family, signaling a hopeful chapter for their future alongside the magic that binds them all.
