Wing-commander Tim Mason leads a squadron of Lancaster bombers on almost nightly raids from England. Having flown eighty-seven missions he will shortly be retiring from flying, but the strain is showing. He tries to make sure his men concentrate only on their job and so keeps women away from the base, but then he himself meets naval officer Eve Canyon.
A British Sanitary Engineer, goes on holiday with a set of plans for a new secret weapon which he has mistaken for his new plumbing invention. Everyone is hunting for him, including the Russians. The Russians find him and offer him a job in the Kremlin doing research (on plumbing he believes). He accepts, arrives in Russia and falls in love with Tania, a secret agent. And then discovers the true nature of the plans he is carrying...
A hunt for a spy, in a hotel in the South of France just before World War Two.