''A Three-Cornered Mystery'' is the fourth book in the classic Dana Girls Mystery Stories series. The novel follows orphan sisters Louise and Jean Dana as they solve complex mysteries while attending Starhurst School.
While visiting their friend Edith Darrow for the weekend, Louise and Jean discover a hidden cache of items in a barn linked to a notorious real estate swindler named Ed Carillo. When they stake out the barn, an injured man stumbles inside. Returning to the main house for help, they find that the home has been completely ransacked and Edith has mysteriously vanished. The sisters must piece together a tangled web of fraud and theft to rescue their friend, recover stolen property, and track down Carillo.
