The legendary Nero Wolfe is hired by a despicable millionaire named Otis Jarrell who is trying to prove that his daughter-in-law is an information-leaking, double-crossing snake. In spite of Wolfe's reluctance, his assistant Archie brashly agrees to perform as Jarrell's personal secretary--under an assumed identity--to gather information about the possible misdeeds of said daughter-in-law. Everything turns serious when one of the detectives' associates is found shot dead--and the evidence points to Jarrell's own missing revolver.