The Pied Piper (Van Johnson) is first spotted working magic in Hamelin by a disabled boy, Paul, and playing his signature tune In the Hall of the Mountain King. Paul tells his best friend, the schoolteacher Truson, also played by Johnson, but Truson is skeptical. The town of Hamelin has entered a competition in order to win a banner from the King. To this end, the Mayor (Claude Rains) exhorts the people to work incessantly, even the children, to the extent that they are denied school and play. Truson protests, but his protests go unheeded by the arrogant Mayor. The Mayor and his cabinet plan to construct golden chimes to impress the King's Emissary, who is due to pay a visit to Hamelin, but their efforts are temporarily halted when the town is invaded by rats, the result of a plague in the neighboring city of Hamelout.