Word has come from the British ambassador Arbuthnot that the neutral Turks are being wooed by the French and if the ancient city of Constantinople falls into their hands, Napoleon's route to India will be completely unfettered and his plans for world domination a reality. Concerned for his safety, Arbuthnot is demanding a large fleet presence to take him off and bring the Turks to their senses. Braving treacherous currents, unreliable winds, and giant bombards, Thomas Kydd returns to sea and rescues the ambassador, but as Kydd waits for the rest of the expected fleet, the French are able to strengthen the Turkish defenses. Meanwhile Kydd's friend and confidential secretary, Nicholas Renzi, has assumed a new and dangerous role that he can never make public. He engineers a coup in the Topkapi Palace that turns the tables on the French but at the cost of both infidel nations being ejected from the Ottoman Empire. When Kydd learns of Renzi's incarceration in a Turkish prison, he knows if will take superb seamanship and sheer bravado to free his friend.