Harry Angel, a down-and-out Brooklyn detective, is hired to track down a singer on an odyssey that will take him through the desperate streets of Harlem, the smoke-filled jazz clubs of New Orleans, and the swamps of Louisiana and its seedy underworld of voodoo. A private investigator is hired by a man who calls himself Louis Cyphre to track down a singer named Johnny Favorite. But the investigation takes an unexpected and somber turn.