«A Nightingale Sang» by Barbara Cartland

Dejected and jobless like so many other Servicemen after the end of the Great War of 1914–18, Tybalt Hampton escapes a ball in Berkeley Square and meets a delightful young girl who has also sought refuge in the little Temple in the nearby gardens because no one has asked her to dance.
It is too dark to make out her face, but in an enchanted moment they kiss in the moonlight and a nightingale sings in the trees above as if just for them.
Two years later the beautiful Aleta Wayte, the recipient of that anonymous kiss, and her brother, Sir Harry Wayte, are forced to let their beloved ancestral mansion to a millionaire American called Cornelius Wardolf, disguising themselves as servants in their own home and at their tenant's beck and call.
Of noble birth but penniless, Aleta still dreams of that handsome stranger. So, when Fate in the form of a road accident brings him injured to her door, her hopes are raised and then instantly dashed.
In her guise as a lowly servant how can she reveal herself as Tybalt Hampton is now the fifth Duke of Stadhampton and anyway, because of his impoverished estates, he has been earmarked by Cornelius Wardolf to marry his attractive daughter, Lucy-May?
Is it possible that Fate could be so cruel as to bring love so close only to snatch it away?