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.
Due to a mix up with his luggage, a young man finds that he now has half a million pounds in stolen diamonds. "The Datchet Diamonds," concerns an Englishman named Paxton (Harrison) whose engagement to lovely Daisy (Miss Grimes) is endangered when he loses all his inheritance money in speculations. Paxton accidentally comes into possession of a quarter of a million pounds worth of stolen diamonds. When the thieves attempt to recover their loot, comic and adventuresome activity results.
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.
A young man takes a room an "The Flying Dragon", a haunted inn that has been the site of mysterious disappearances.
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.