In a quiet room in the White Swan Inn, sunlight slowly breaks through the curtains revealing two young lovers—an American seamstress and an English officer. They have been brutally, ritualistically murdered in their sleep. It is a grisly scene that can only mean one thing: There is a traitor within the American Revolution.

The year is 1779. General Washington, struggling to keep his army together, sends his best spymaster, Matty Grove, to investigate the killings. As Matty follows the trail of clues, he comes up against more questions. Who gave the killer his orders? How much does the mole know of the Revolution’s plans? Is this treason a matter of principle or simply profit?