When her grandmother dies, Paola, the beautiful young daughter of the Earl and Countess of Berisforde is dismayed to find that the family's customary six months' mourning means that she will miss her debut in the London Season.
Instead her mother sends her to stay in the ancient and historic Italian town of Lucca with her aunt, the Contessa Raulo, who is to be her chaperone.
Paola's adventurer cousin Hugo arrives just before she leaves and asks a favour of Paola that is to prove fateful.
Having promised her mother that she will avoid him at all costs, Paola must now seek out a notorious 'ladies' man', the Marchese Vittorio di Lucca, and deliver a precious package to him.
It is a huge diamond set in a ring that had been presented some years earlier to the Marchese by the Nizam of Hyderabad, which had been stolen and which Hugo had brilliantly retrieved at great risk to his life.
Within the spectacular mediaeval ramparts of Lucca, Paola accomplishes her mission, falls in love with the beautiful town – and then, after a terrifying ordeal at the hands of murderous thugs, with its most prominent citizen as well!