HMS Leopard sails from Desolation Island to Port Jackson where she dropped off her few prisoners. Captain Bligh is already handled, so she proceeds to the Dutch East Indies station and Admiral Drury at Pulo Batang. Leopard is declared unfit for guns due to wood rot, and will probably be a troop transport. Jack Aubrey and his followers are to board La Flèche courier ship, as his next command, Acasta , awaits him in England. The rest of the crew is left with Admiral Drury. Maturin learns the success of his scheme to damage French intelligence sources from Wallis, and relays the name of a contact in the Royal Navy, mentioned by Louisa Wogan. They join a cricket game, ended abruptly by the arrival of La Flèche , which also brings mail to them. Captain Yorke visited Sophia Aubrey before leaving England, bringing Jack a personal letter and gifts from her.
Aubrey knew Captain Yorke and Maturin quickly warms to this captain who travels with an extensive library and a piano in his cabin. At Simon's Town, La Flèche learns of war between Britain and America. Aubrey spends this time of sweet sailing teaching the young midshipmen while Maturin is engrossed in dissection of specimens from Desolation Island and New Holland with McLean, the ship's Scottish surgeon, passing their evenings with music. One night in the Atlantic near Brazil a fire breaks out on board and all abandon ship to the small boats. A few hot weeks later one boat is picked up byHMS Java
on Christmas Eve, headed for Bombay and commanded by Captain Henry Lambert.
Soon the watch sees a ship hull-up on the horizon, theUSS Constitution
, which Java immediately pursues. Aubrey and his Leopards man two guns but the fight goes badly when the Java' s foremast gives way. The American commander makes few mistakes and soon the Java strikes its colours. Constitution returns to Boston to refit, having taken part of the Java for its own repair, then setting fire to her. Captain Lambert dies of his wounds ashore in Brazil. Aubrey is shot in his right arm, gravely wounded, and too ill to be put ashore. Maturin stays with his patient, and works with Dr. Evans, the amiable ship's surgeon. All of Maturin’s collections, except what he noted in his diary by words or drawings, are gone. During the voyage Maturin talks with a French passenger picked up at San Salvador, Pontet-Canet.
In Boston, Aubrey convalesces from his wounds in Dr. Choate's hospital, waiting for the next prisoner exchange. Jahleel Brenton of the US Navy Department questions him, but Aubrey puts him off and pushes him out, realizing now why his exchange is taking so long. Maturin is reacquainted with both Louisa Wogan and Michael Herapath, and then meets their daughter Caroline and Michael's father George. George is a wealthy merchant and a Loyalist in the Revolutionary War whose trade with China is interrupted by the present war. Maturin encounters Diana Villiers, still the mistress of Harry Johnson. He is a wealthy American slave owner from Maryland who is active as a spy for his nation. Johnson visits Aubrey who makes a comment about Maturin that reveals too much to the bluff spy. Maturin suspects that Johnson and Pontet-Canet have turned their attention away from Aubrey, towards him. He asks George Herapath to bring Aubrey a pair of pistols.
Aubrey watches the harbor from his hospital bed. Pontet-Canet tries but fails twice to abduct Maturin in the streets of Boston. After the second try, Maturin meets Diana Villiers in the Franchon hotel when Johnson is away with Wogan. While searching Johnson's papers, Maturin kills first Pontet-Canet and then Jean Dubreuil as they come to Johnson's room. Maturin finds that Johnson had intercepted Diana's letter to him. He offers to marry her to solve her problems of citizenship. Diana wants away from Johnson. Maturin sends a note to Aubrey setting up a plan of escape that night. George Herapath allows the two to hide in one of his larger ships.
Then Aubrey sails a small fishing boat and he, Maturin and Diana meet the thirty-eight gun frigate,HMS Shannon
, entering the outer harbour on blockade duty and are taken on board by Captain Philip Broke, Aubrey's cousin and childhood friend. Broke writes a challenge to Captain Lawrence, the new commander of the thirty-eight gun
USS Chesapeake lying in harbour, to fight one-on-one, which letter never reaches him. The Chesapeake comes out in apparent pursuit of Aubrey and engages the Shannon . The battle lasts fifteen minutes, until Chesapeake strikes her colours to Shannon . Aubrey led a gun crew, his right arm tied to his body, while Diana sits in the forepeak and Maturin waits below with the surgeon in this victory for the Royal Navy.