Fern is a girl of high principles and such people are born to be tested. When Fern's allowance from her father suddenly stops, she and Terrence Barrett, her feckless husband, are forced by circumstances to take employment as cook-housekeeper and chauffeur at Swanlake Manor. The beautiful Sussex manorhouse owned by a powerful financial tycoon, Quentin Dorey. With their jobs as servants at the household of famous bachelor, her trials begin. Terry becomes increasingly self-centred and feckless, while Fern finds herself more and more attracted by the charm and sympathy of their employer. She also incurs the hatred of Quentin's embittered mother, who has guessed something about the girl's background which Fern is desperate to conceal. What is Fern to do? Because for her, alas, a promise is for ever... but she paid a bitter price for keeping it!