On a gloomy December day during the American Revolution, two strange vessels were seen hovering off the east coast of England, in that expanse of water known at the time as the German Ocean. One, a small black schooner, moved slowly amid the sand bars and sunken rocks with which the immediate coast abounded. The second was a gallant ship of the frigate class, and floated majestically in the tide drawing closer to the smaller vessel. These were an American frigate and its consort, the "Ariel" on a secret mission among the dangerous shoals and reefs of the English coast.

It is February 1818, and Adam Bolitho longs for marriage and a safe personal harbour. But with so much of Britain's fleet redundant, he knows he is fortunate to be offered H.M.S. Onward, a new 38-gun frigate whose first mission is not war but diplomacy, as consort to the French frigate Nautilus. Under the burning sun of North Africa, Bolitho is keenly aware of the envy and ambition among his officers, the troubled, restless spirits of his midshipmen, and the old enemy's proximity.