At Santa Claus School, the principal has called a meeting. Lucia, her parents Julius and Claudia and everyone else at school are excited. But the tension is replaced by a shock when the headmaster cancels Christmas. He seems confused, and it soon becomes clear that he is trapped in a Christmas trauma from his younger days as Santa Claus. Lucia sets out to find out what has happened and with the help of the younger student Elias and a magical time machine, she travels back in time in the hope of saving Christmas.
