Eva wants to become a singer and ends up in the Mambo bar, where behind the scenes is traded with other goods than talents.
Eva, a young woman intent on becoming a successful singer, goes to Martini, a man whom she has never seen, looking for employment. Martini, owner of the Mambo-Bar nightclub, finds her a job in the same building handling bookings for a theatrical agency. Tommy, the trumpeter in the jazz band at the club, encourages Eva to sing with his combo, thus angering Olga, the drug-addicted dancer at the cabaret. Olga tries to murder Eva but instead falls to her own death. Tommy, an undercover agent, intervenes in the bar's illicit operations in topless massage parlors, narcotics dealing, and espionage. Attempting to escape, Martini is fatally shot, but before dying he reveals to Tommy that he is Eva's father. Tommy keeps this information to himself, and he and Eva leave together.
