The mayor of Sunny Dale see a chance to get rid of the Flodder family: They send the asocial bunch for an international exchange to New York. There they get confused with a Russian delegation of medical doctors while the street worker Werner who accompanies them becomes imprisoned.

The Baron and his cronies steal a precious crown and hide in a secret room of an abandoned castle. With the help of their tiny robot Robin, Bassie and Adriaan set out to find the crown and return it to the museum.