Carleton Allen, son-in-law of a millionaire tycoon and nervous of publicity, explains to Bertha Cool and Donald Lam that he's mixed up in a first-class scandal. He's spent the night with a blonde while his wife was away, and that same night at the motel a man was murdered.

Donald doesn't believe the story, but the large retaining fee is too great a temptation to Bertha. So, once again, the intrepid partnership is off on a dangerous mission involving blackmail - and murder ...