1914. The monarchs of Sweden, Denmark and Norway meet to demonstrate unity. In the crowd is a beautiful noble woman from Finland. She is eagerly courted by the monarch's aides.
Two inventors, Ville and Rulle have developed a revolutionary new accordion; however, they have competition. Twelve-year-old Pelle Borell gets to show off the instrument in front of the Swedish accordion elite in Stockholm.
To save intoxicated friend Boman from getting caught, two conscripts lock him up in the local jail and release a prisoner, Ivan Jansson, so that he can pretend to be Boman for a few hours. But when the real Boman is transported to the county jail, switching them back could be difficult.