Riding to the Moon by Barbara Cartland

Lord Frodham and his friend Sir James Overton lay a wager that they can dupe the snobbish, horse racing-obsessed Marquis of Ardsley into falling in love with some beauty of the lower orders. They can hardly believe their luck when by chance they rescue lovely young heiress Indira Rowlandson from her dead father’s evil lawyer who is bent on marrying her off to a bankrupt stranger. Indira is set on joining a Convent to escape the unwanted attentions of men, whom she hates, but, agreeing to their plan out of gratitude, she finds herself among high Society at Ardsley Hall. And, finding that the imperious Marquis shares her passion for the mysteries of the Orient, in spite of herself she begins to fall in love.