What would you do, if a fully grown elk were to crash noisily through the roof of your house and end up sitting in the middle of your living room? An elk who can talk, who goes by the name of Herr Moose and who claims to have lost control of the sleigh while on a test flight with Santa Claus, hence the crash. Little Bertil is enthusiastic. At last he has a friend to do crazy things with, a friend who stands up for him at school and, above all, who understands him. All would be in order, were it not for the smarmy Pannecke, farm owner and landlord, who sees his great opportunity of fulfilling a dream and shooting an elk. To cap it all, Santa Claus in person announces that he wants to come and collect Mr. Moss. What is Bertil to do?