 August 1940: During the blitz, a man is found in his bombed-out house, stabbed in the chest. The man was a lorry driver who was transporting works of art to Wales for safekeeping. Foyle suspects that the man s job and the art work are somehow related to his death. Foyle s son Andrew, an RAF pilot, stops in en route to his first operational assignment. Disappointed at not being assigned to a squadron, he finds that he is to assist in the development of a new technology - radar. Things get dicey when Andrew is accused of giving information to the enemy. Sam receives a visits from her clergyman father who insists that she pack it in and return home.