The three kids are Danny, Brian, and Mary. Their dad, Wayne, is a widower and a struggling car salesman who decides to move his family to Edmonton for a fresh start. They rent a house in a subdivision and try to adjust to their new life.
On their first visit to West Edmonton Mall, Danny finds a bag of money in a trash can. The three kids decide to keep the money and go on a shopping spree. They soon realize that the money is fake and that they have unwittingly become involved in a counterfeiting scheme.
Meanwhile, two crooks named Harry and Jack are also in the mall, trying to get rid of their fake money. They meet the kids and realize that they can use them to exchange their fake bills for real money. The kids are initially fooled by the crooks but eventually wise up and decide to turn them in to the authorities.
With the help of a security guard named Brian, the kids set a trap for the crooks and catch them in the act. The crooks are arrested, and the kids are hailed as heroes.
In the midst of all this excitement, the kids also discover a secret about Santa Claus. They find a special room in the mall where he meets with children and learn that he is not just a jolly old man but also a skilled craftsman who makes toys for children around the world.
The movie ends with the family celebrating Christmas together, with Wayne realizing that the move to Edmonton might have been the best thing that ever happened to them.
