This romantic Second World War thriller begins with Lily Rood, an innocent eighteen year old girl, preparing to join her friend, Sally, at a summer school in Munich. It is 1938 and the trappings of Nazi power are all around her. She meets and falls in love with Friedrich, an ardent member of the Hitler Youth. Despite Sally's warnings about the ugly incidents they witness, it is only when she gets back to England and is accused of being pro German that Lily realises how naive she has been. But she still desperately loves Friedrich. When war breaks out, Friedrich's knowledge of England gets him assigned to a small espionage unit sent to blow up a munitions factory. The mission fails and he is captured. His known association with Lily brings her to the attention of the authorities. She is arrested and questioned as a suspected spy. She is able to prove her innocence, but Friedrich is sent to a POW camp, vowing to hunt down those who betrayed him. Lily is released and takes a job as a lorry driver at a brick works. Her relationship with Friedrich makes her useful to MI5. She is recruited as a double agent and is sent to London on an assignment, where she experiences a bombing raid and is set up as a pawn in a plot to trap a spy. As recognition of her participation she is allowed to visit Friedrich but finds he has lost none of his Nazi zeal. The war has toughened Lily and she has grown disillusioned with her attachment to Germany. To save Friedrich from himself and to save their relationship, she must now do everything she can to keep Friedrich in England.