Professor Harold Hill likes a challenge and when the other salesmen on the train west tell him that Iowa is the biggest test of all of sales ability, he gets off at River City. We know it's the 20th century there, only because of a reference in one of the songs to Gary, Indiana. Marian the librarian doesn't buy the professor's line but he convinces many of his other potential customers that the new pool table that has just been placed in the billiard parlor could mean "trouble in River City." How to keep the youngsters "moral after school?" Form a boys marching band.