Set in upstate New York on a comfortable estate, the law-abiding family of Mr. Wharton suddenly finds the Revolutionary War at its door. They are an American family with friendly British ties, but they have kept their dual loyalties from affecting their peaceful life, until a secret visit from Wharton's own son, Henry, changes everything.
Henry is a British officer and has crossed behind American lines in disguise. When American troops arrive unexpectedly, Henry is discovered and arrested as a spy. Adding grief to the family's pain is the connection to Henry's captor, the noble Major Dunwoodie. He is Henry's sister's fiance and Henry's own childhood friend; and they must all remain at the Whartons' until Dunwoodie can escort Henry to Washington for his trial.
The plans for departing are delayed when British forces enter the vicinity and a battle breaks out within sight. When the British are defeated, Dunwoodie quarters captured Colonel Wellmere in the Wharton home. Now quarantined with prisoners and quartered American officers, the Whartons wait for their beloved Henry to be taken away and tried. Little does any of them know that the real spy still roams free and plies his trade within their midst.