Frenchman's Creek - Daphne Du Maurier

Lady Dona St Columb seems to revel in scandal: she is involved in every intrigue of the Restoration Court. But secretly, the shallowness of Court life disgusts her, and in her heart she longs for freedom and honest love. Retreating to Navron, her husband's Cornish estate, she seeks peace and solitude away from London. But Navron is being used as the base for a French pirate, an outlaw hunted all over Cornwall.

Instead of feeling fear, Dona's thirst for adventure has never been more aroused; in Jean-Benoit Aubéry she finds a sensitive man who would, like her, gamble his life for a moment's joy. Together they embark upon a quest rife with danger and glory, one which will force Dona to make the ultimate choice: will she sacrifice her lover to certain death, or risk her own life to save him?