Jeff Lambert (Bing Crosby), who has grown up in New Orleans surrounded by black music, determines to start a band featuring white coronet player Memphis (Brian Donlevy). However, the Basin Street Hotshots are rejected from several venues for playing "black" jazz, until singer Betty Lou Cobb (Mary Martin) insists they be hired as her backup band. The band finds success until Jeff and Memphis fall out over Betty Lou, then get entangled with gangster Blackie (J. Carrol Naish).