Jack Aubrey and Sophia Williams are married and the parents of twin girls. They live at Ashgrove Cottage on his half-pay, not enough to support fellow navy men in the household. Sophia's mother lost her money, including Sophia's portion, and now lives with them. They have Cecelia, Sophia's young niece in their household as well. As much as he loves Sophia, Aubrey is ready to go to sea again. Stephen Maturin comes to call, and soon after Aubrey's orders are delivered from the port Admiral. He is given command of the 38-gun frigateHMS Boadicea
. At Plymouth, he picks up orders and Mr R T Farquhar, a political gentleman. He is to sail to the station at Cape Town where the ships of a convoy will meet. Not long away from home, they meet with the French ship Hébé which is escorting a captured merchant ship. The Boadicea captures both ships. He sends the prizes to Gibraltar. The timely capture allows the ship to send letters home, gain a French cook and the Hébé's English prisoners, able seamen. The long journey in the Atlantic gives Aubrey time to bring the crew of the Boadicea up to his standards of efficiency in gunnery, and gives Maturin and Farquhar time to develop strategies.
On arrival, Aubrey meets Admiral Bertie who confirms Aubrey's position as Commodore and his broad pendant is flown. He receives formal instructions to disrupt French interests in the region, and ultimately to take the islands of Mauritius and La Réunion. The convoy includes Lord Clonfert of the Otter , an Englishman with an Irish title; Captain Corbett of Néréide ; and Captain Pym of the Sirius . Corbett sailed from the West Indies station with some of Aubrey's followers aboard. Bonden, Killick and others join, after Aubrey trades men into Corbett's ship. Corbett is capable but a flogging captain. Bertie advises Aubrey that Clonfert and Corbett are not on good terms with each other.
For the first 2,000 mi voyage to the islands, Aubrey switches his pendant to the elderly 64-gun ship of the line HMS Raisonnable . The Caroline is taken; Corbett sails her, christened HMS Bourbonnaise , with dispatches to Cape Town and England. The rest of the convoy returns to Cape Town. Aubrey shifts back to HMS Boadicea and sails upon news of more merchant ships taken by the French. The convoy is caught in a major hurricane, whence it sails back to Cape Town for repairs, receiving the first mail in many months. Sophia's letters are water-damaged, so Aubrey does not understand her full message.
La Réunion capitulates almost without loss after a landing by Army troops joined by sepoys under the British East India Company, all under the active and decisive Lieutenant Colonel Harry Keating, with ships of the convoy on both sides of the island. Their path is eased by Maturin's propaganda and political meetings to explain why the locals should be happy to accept the British, with Farquhar as interim Governor. Mauritius proves more challenging. Maturin has an accident boarding HMS Néréide , which is part of the force sent toÎle de la Passe. He is seriously injured, so he observes Clonfert during this recuperation aboard. The action is successful. Maturin is put down on Mauritius to continue his work. A small group of ships, under the command of Captain Pym, puts soldiers on Mauritius to staff the fort. The French appear with three ships Bellone , Minerve , Victor and two Indiamen Ceylon and Windham . They boldly attack the fort and then sail into the port; the British are caught unprepared but decide to attack. The struggle goes on for days with heavy casualties and in the end two British ships run aground. Sirius and Magicienne are burnt to prevent their capture, and Iphigenia and the fort atÎle de la Passe are abandoned to be retaken by the French. Néréide is taken and Clonfert is severely wounded in the neck and head by a splinter. A messenger vessel, with Maturin aboard, reaches La Réunion to inform Aubrey of the losses and the failed attack on Port Southeast.
Boadicea sails the night to checkÎle de la Passe, to see it under French control; then Boadicea chases Manche and Vénus , in a vain attempt to separate them. After making contact with Pullings, who has the guns of Windham aboard Emma , Aubrey believes his fortunes have changed. Then Captain Corbett re-joins at St Denis, with HMS Africaine . Chasing the French during the night, Africaine clashes with the Astrée and the French Iphigenie . The encounter goes badly and Corbett is killed during the fight after being wounded, possibly by his own oppressed men. The French capture the Africaine , but leave it dismasted when the Boadicea bears down on them; Astrée refuses an engagement. Joined by the Otter and Staunch , the flotilla reaches La Réunion where refit of the Africaine is the Commodore's top priority.
Maturin and Bonden return from Mauritius with news that HMS Bombay is nearby, in a running fight with both the French Vénus and Victor . The Boadicea engages the French ships. Aubrey makes use of volunteer crew from the refitting HMS Africaine to board and capture Bombay and Vénus . During the encounter the French Commodore Hamelin is killed. Aubrey plans how to finish the battle, once the remaining French ships will be ready to sail, and his ships are ready to fight again, when they reach Mauritius. Keating is equally ready. The Emma nears the Boadicea , with many other British sails in view. Tom Pullings comes aboard with the Gazette announcing the birth of a son to Sophia. Aubrey is ecstatic at the news. Then he opens Admiral Bertie's letter ordering him to join the fleet at Rodriguez, where he will be on HMS Illustrious , and the Army led by General Abercrombie. The final invasion, based on Aubrey and Keating's original plan, is almost without bloodshed. The French capitulate after being given honourable terms.
Maturin finds that Clonfert, at the military hospital in Port Louis since the battle, has committed suicide, unable to face Jack Aubrey, whom he considers a rival. A ceremonial dinner is given at Government House. Maturin spreads rumours about Aubrey's father soon to have power in London, via Mr Peters, which rumours are believed by Bertie. The Admiral gives Aubrey the honour of taking the dispatches of this success aboard the Boadicea to England.