After their annual free concert at Chicago's Dearborn Settlement, Benny Goodman and his band are packing up to go to their next engagement when a kid steals Goodman's clarinet. Goodman and Popsie pursue him to a tenement flat where he has led them to hear his brother play the trombone. Shenanigans ensue following Goodman's offering the brother a job with the band.

The lives of a close-knit group of brothers growing up in Iowa during the days of the Great Depression and of World War II and their eventual deaths in action in the Pacific theater are chronicled in this film based on a true story.