A travelling con-man salesman, Professor Harold Hill, stops in early twentieth century River City, Iowa, to convince the town that they desperately need a boy's band. Everyone falls for his game...

A travelling con-man salesman, Professor Harold Hill, stops in early twentieth century River City, Iowa, to convince the town that they desperately need a boy's band. Everyone falls for his game except the one person he needs to win over, the local piano teacher and librarian, Miss Marian Paroo. Complications arise when River City's mayor wants the Professor's credentials, another travelling salesman tries to expose Hill, and the librarian finds herself falling for Harold!