Sixten is really good at singing and writes his own songs. The only problem is that he doesn't really dare to show it to anyone. But all that changes when he makes a wish one evening at a magical Santa Claus in Tivoli.
Big Christmas hits like Last Christmas and All I want for Christmas have disappeared. Sixten plays them for his teacher Eva, who encourages him to record them, and before Sixten knows it, the song has been shared everywhere.