On Valentine's Day, neglected wife Mary comforts heartbroken coworker Alan in the empty office, turning sympathy into intense, passionate sex. She returns home to her oblivious husband, uses the "sex-scented" office perfume as cover, and reignites their marriage with explosive intimacy—secretly satisfied by serving both men perfectly that day.
Lt Tony Nash RNVR was badly wounded on the return from Dunkirk whilst in command of a commandeered paddle steamer. He was awarded the DSC for gallantry, but he was temporarily unfit for sea service when he left hospital. He was then attached to a special anti-spy unit searcing out Nazi sympathisers whio had entetred Britain under cover of the evacuation.