It's the night of 12 November 2019. The worst flooding in 50 years hits the city of Venice.

85% of La Serenissima is underwater. Gale force winds roar across the lagoon and along the narrow streets. And the body of Dr Jennifer Whiteread- a young British art historian, specialising in the depiction of angels in Venetian painting - is found floating in a flooded antique bookshop on the Street of the Assassins.

As the local police struggle to restore order to a city on its knees, Nathan Sutherland - under pressure from the British Ambassador and distraught relatives - sets out into the dark and rain-swept streets in an attempt to discover the truth behind Whiteread's death. The trail leads to the "Markham Foundation", a recent and welcome addition to the list of charities working to preserve the ancient city. Charming, handsome and very, very rich, Giles Markham is a well-known and popular figure in the highest Venetian social circles, and has the ear of both the Mayor and the Patriarch.

But a man with powerful friends may also have powerful enemies. And Nathan is about to learn that, in Venice at least, angels come in many forms - merciful, fallen and vengeful...