The case of the drowning duck

As the book opens, Perry and his secretary are away from the office on vacation in Palm Springs. And it turns out to be fortuitous when Mason is approached by a very wealthy local man, named Witherspoon, who has a strange request.

Witherspoon's daughter has fallen in love with a young, penniless college student named Marvin, who will soon be going off to fight in the war. Marvin and the daughter believe that he was kidnapped as a baby and was raised by the woman he thought was his mother, until she died making a deathbed confession about the kidnapping. However Witherspoon has conducted an investigation and knows that the story was false. The boy's father was hanged for murder years earlier and the mother made up the lie to spare the boy the embarrassment of knowing that he was the son of a convicted killer.

Witherspoon is determined to protect his family's good name at all cost and is determined that his daughter will not marry the son of a man rightfully convicted of murder. He has a copy of the trial transcript and wants Mason to review it. If Mason can convince Witherspoon that the man was wrongly convicted, Witherspoon will say nothing and will allow his daughter to marry Marvin. But if there's even a breath of suspicion left, Witherspoon will expose the secret and forbid the marriage.

Mason thus faces several seemingly impossible tasks, the most important of which is saving the young lovers from the stupidity and narrow-mindedness of the girl's father.