Sergeant John Patterson of the U.S. Air Force, billeted in the Grosvenor Square house of the Duke of Exmoor, is invited to the Duke's castle and, after a cool beginning, comes to know and love his granddaughter, Lady Patricia Fairfax, now a W.A.A.F. corporal. Patricia returns his love, but is already engaged to an Englishman, Major David Bruce. The latter gives her up under protest; but John feels that he is in the wrong and ceases to see Patricia, who makes it up with David. Subsequently the Englishman, realising that she is really in love with John, does the noble thing in his turn and relinquishes with dramatic consequences.