Captain Jack Aubrey is ashore on half pay without a command, until Stephen Maturin arrives with secret orders for Aubrey to take a frigate to the Cape of Good Hope under a commodore's pennant. Once there he is to mount an expedition against the French-held islands of Mauritius and La Réunion. But the difficulties of carrying out his orders are compounded by two of his own captains—Lord Clonfert, a pleasure-seeking dilettante, and Captain Corbett, whose severity pushes his crew to the verge of mutiny.

This fourth action-packed installment in the Aubrey-Maturin series, as with the rest, demonstrates historical fiction at its best.