The poker-wielding Duke of Dunstable, the rudest man in Shropshire, has brought his niece Linda to Blandings in order to keep her away from the financially embarrassed Pongo Twistleton. Believing that Clarence wants his beloved pig to run in the Derby, the Duke plots to have Clarence committed; but Freddie has Pongo pose as London’s top psychiatrist in a precarious plan to unite the star-crossed lovers and save Clarence.