A sinister criminal known only as "The Bat" attempts to locate a fortune in stolen securities supposedly hidden in the rambling mansion owned by spinster Cordelia Van Gorder.
Edward Stevens, is on the train home, recounting the story of the death of the rich uncle of his neighbor, Mark Despard. Once he arrives home, he is no longer sure that his uncle died of natural causes.
Shortly after an encounter with a strange woman dressed in white, an artist travels to a remote country house, where he is to teach drawing to two sisters - one of whom resembles the woman in white.
A madman known as "The Cat" has escaped from a lunatic asylum and threatens an ill-assorted group of people assembled for a will-reading at a lonely house.
German Leopold von Ragastein meets his doppelganger, Englishman Everard Dominey, in Africa, and plans to murder him and steal his identity to spy on English high society just prior to World War I.