 In the 1890s, Sgt. Major John Philip Sousa, leader of the Marine Corps Band, meets Private Willie Little, inventor of an instrument he calls the Sousaphone...and Little s girlfriend, shapely showgirl Lily. To support his growing family, Sousa leaves the Marines and forms his own band; Willie and Lily go along. Though he d rather write ballads, Sousa s marches bring him increasing fame; from their debut in 1892 the band is a great success. But Sousa s  no wives  rule threatens the romance of Willie and Lily...as does the Spanish-American War.