Peter Gunn is hired by a man known as the Baron to protect Rowena, the roommate of a murdered carnival dancer. Rowena is the Baron's girlfriend, and when she becomes infatuated with Gunn, the Baron threatens the private investgator.

Arnie Kelton musician and ex-convict, asks Gunn to investigate his wife's death.

Nightclub Singer Julie Kent is murdered and the DA's son is the suspect, she also happens to be the ex-girlfriend of syndicate boss DeSantis.