In two different, but invisibly interconnected worlds, the New Year is approaching. Unfortunately, for some it may be their last. In the world of magic, there is a fairy tale about Santa Claus, who flies on a mechanical sleigh with rotating iron wings. My mother tells this story to a seriously ill girl, Lika, whom even the spells of the best doctors cannot cure. In our world, the boy Fedor, the son of a world-famous physicist, is in a similar situation. Children don't know about each other. They are separated by a seemingly insurmountable line between worlds, but they can only survive together.