Master baker Klaudia Wehmeyer loves her job more than anything. But now the spirited owner of a small fine-pastry shop must answer in court: Roland Müller, the shrewd managing director of the company, and greasy partner Dr. Frank Lehmann accuse Klaudia of embezzling half a million euros. Despite her pleas of innocence, the court sentences her to three years' imprisonment. Stunned by this injustice, Klaudia flees the meeting room, disguises herself with a stolen Santa Claus costume and tries to break into Lehmann's villa to collect evidence of her innocence, but she promptly triggers the alarm and must flee headlong to the neighboring property. Here she meets siblings Pia and Tim, to whom she pretends to be Santa in their distress; the trick works and the children give shelter to their discovery. Their father, Paul Weber, isn't happy about the unusual guest and unceremoniously shoves her at the door. The personable single father has enough worries: the delicatessen he ran was sold to a large company--and its slick owner Karsten Klett has not only laid off almost all the employees in the business, but now also wants to drive Paul out of his small house because he's after the property. Meanwhile, Klaudia is quartered in the children's tree house and waits for another good chance to break into Lehmann's villa. When Paul discovers her there, he begins to realize that the Santa Claus costume is anything but a simple crook. To his children's delight, he invites "Nikolaus" into his home--and soon his initial skepticism gives way to other, deeper feelings. Thanks to Klaudia's help, it is possible to dissuade the nasty Klett from his plans. Then a misunderstanding threatens to end the blossoming love between Klaudia and Paul.