North America's French and Indian War may be over, but at the end of 1760 the wider Seven Years War is still raging in Europe and across the seas of the world. Nevertheless, the New England merchants are growing restless at the restrictions on their trade with the French islands, and one Rhode Island company is determined to defy the law and bring home a cargo of contraband molasses.

Edward Carlisle's ship Dartmouth is assigned to the Leeward Islands Squadron, tasked with blockading the remaining French Caribbean sugar islands. When he intercepts a New England ship suspected of trading with the enemy, he is left with a dilemma between his duty to his king and his loyalty to the colonies where he was born. What should be an open-and-shut case in the admiralty courts proves to be nothing of the sort.

Meanwhile, the French navy can still influence events, as Carlisle discovers when he is confronted by an enemy battle squadron with only a frigate to support him.

Carlisle's Duty is the eleventh Carlisle and Holbrooke novel. The series follows the two sea officers through the Seven Years War and into the period of turbulent relations between Britain and her American colonies prior to their bid for independence.