Miss Susan Baird and her niece, Miss Katrina Baird, known better as "Kitty Baird," lived alone in the family mansion, of which they used only part, for as often happens in that part of the country, they were known to be gentlewomen of reduced means—their living expenses being met by the girl, who had held a government clerkship. An old family servant did a little work each day, coming in from his home. On Sunday afternoon the servant left the house while Kitty and Miss Susan are having one of their too frequent quarrels.

The next morning Miss Baird's physician, Dr. McLean, called to her home finds upon his arrival that it is in charge of the police officials, and is told that when they entered the house they found only a dead woman and a live one. The plot thickens; there is an attempt to kill Kitty's sweetheart, Edward Rogers, who seems to be following a definite plan in tracing the murderer, twice at least the mansion is ransacked. A little known woman from California, an army officer formerly from there but now of Washington while being treated at the Walter Reed Hospital for shellshock, a lawyer, a jealous husband, all add to the uncertainty.