1796: Nathan Peake, captain of the frigate Unicorn is sent into the troubled waters of the Adriatic. His mission: to scourge the sea of pirates and turn the Serene Republic of Venice against Revolutionary France. But Nathan is soon drawn into a much more sinister web. At its heart two of the most feared women of the age: Emma Hamilton, the courtesan turned courtier, and the nun Caterina Caresini, uncrowned queen of Venice. And most feared of all, the mysterious agent of the Three Inquisitors, known as Il Diavolo, the Devil. As Nathan confronts the politics of 'intrigue, poison and the stiletto', he plays a deadly game with the ambitious young general Napoleon Bonaparte. In a bid to save the British fleet, Nathan escapes and joins forces with Horatio Nelson for a dramatic break-out from the Mediterranean and a perilous battle off Cape Saint Vincent that could change the course of the war.