Lisbon 1941. Britain and Germany are at war inside a neutral country. The conflict between them has been reduced to a 'cat and mouse' game of espionage, dirty tricks and informants, as each side strives to gain the upper hand without upsetting their Portuguese hosts. Colonel Hulse, chief of Britain's MI6 station in the city believes he has a German mole in his organisation. The German Abwehr chief, Stenzel, has someone close to him who is ready to defect. An agent of the Portuguese secret service, the PVDE, has something of value he wishes to sell. They were all playing a very dangerous game.