Ambrose Frayne introduces his new wife Dominique to his private detective agency partner Charlie Charles. When Charles is found unconscious, the file for the investigation of Lady Graydon's stolen necklace, is now marked 'closed'.

Ambrose and Niki break into Feinter's safe but the necklace is missing. They do however discover a dead body. When arrested leaving by the police Feinter's alibi's them out. The pair learn the dead body is con man Roger Curran.

Insp. Roth gets an anonymous call that a body is at Frayne's home. Niki takes Ambrose to meet her father so Charles remove it's from the premises. Dom needs to move the dead body but vanishes. Niki stumbles on a murdered man in a car.

Ambrose and Niki break into Feinster home and leave a note requesting he returns Lady Graydon's necklace. Feinster retaliates by hiring Cokey Brock to hurt the Frayne's. The pair walk into a trap leaving a nightclub.

Ambrose booby trapped home thwarts Feinster's thugs. His associate Crozier returns Lady Graydon's stolen necklace in a bid end Ambrose investigation but they are fake. Niki goes under cover as a calendar girl.

Feinster and his silent partner Crozier fall out over the fate of the diamonds before he is disposed of. Niki is kidnapped but Ambrose aids her escape to thwart Feinster attempts to get the diamonds out of the country.