Night crossing - Robert Ryan

In 1938, Ulrike Walter, a beautiful young German musician, is engaged to be married to Erich Hinkel, a member of the Hitler Youth. But when she meets Inspector Cameron Ross, a Scotland Yard policeman, whose father is a colonel in British Intelligence, her life will be changed for ever. When war is declared, Ulrike flees Germany for the safety of England but is instead cruelly imprisoned as an enemy alien. Her only hope of rescue is Cameron, who, despite his better judgement, is falling in love with her. And then Erich is captured by the British and incarcerated in a prisoner of war camp in England. He faces interrogation by Cameron Ross, the one man who stands between him and Ulrike, the woman who means more to Erich than life itself.