The Cahills are the most powerful family the world has ever known. However, the family is fractured, and the source of its power has been lost. The story begins with the death of matriarch Grace Cahill. In her will, she leaves her heirs a choice: they can either receive a million dollars or a clue.The Cahills are the most powerful family the world has ever known. However, the family is fractured, and the source of its power has been lost. The story begins with the death of matriarch Grace Cahill. In her will, she leaves her heirs a choice: they can either receive a million dollars or a clue.