When the Duke of Denver learns his sister's fiancé is a card cheat, the engagement is broken and his subsequent murder's blamed on the Duke.

Winsey's search for his future brother-in-law’s murderer leads him to a farmer who's pathologically jealous of his younger wife.

Lord Wimsey investigates his sister's flirtation with Bolshevism and a romantic involvement with a Communist activist.

Lord Peter almost loses his life in the bog but is rescued and recovers in Grimthorpe farmhouse, where he stumbles onto some crucial evidence.