The Commodore
Patrick O'Brian
 The Commodore opens with Jack winning the Ringle, a Baltimore Clipper, from his friend Captain Dundas, the having accompanied the Berenice back from Chile. Aubrey and Maturin have returned to England, (after adventures in the South Pacific and South America) where the latter finds that his young daughter Brigid appears to be an "idiot" or "natural" (to use the language of the time) and unable to speak, and that his wife Diana has fled the situation, leaving Brigid in the care of the newly-widowed Clarissa Oakes. When Stephen meets Sir Joseph Blaine at Black's, their club, he is told that Clarissa's information led to the Duke of Habachtsthal being supposed the third conspirator in the Ledward-Wray conspiracy. Unfortunately, the Duke is too highly placed for Blaine's investigation to do much good and in fact does even more harm to Stephen and his friends. Blaine tells Stephen that the Duke's influence has delayed the pardons of both Clarissa and Padeen as well as instigated an investigation into Stephen's role in the Irish revolt. After hearing this information, Stephen asks Jack for the Ringle and sets off to cash out his bank accounts and then proceeds to have Clarissa, Padeen and Brigid taken to live at the Benedictine house in Ávila, Spain out of the clutches of the Duke. Blaine hires Pratt, whom Stephen had employed in The Reverse of the Medal, to gather information on the Duke. Once the squadron is formed, Aubrey and Maturin are very publicly instructed to disrupt the African slave trade, now illegal, but the true mission of the squadron is to intercept a French invasion force which expects a sympathetic welcome in Maturin's native Ireland. The squadron begins on a difficult note, when the Admiralty reassigns the powerful frigate Pyramus, replacing her with the smaller frigate Thames instead. Also, the Stately is commanded by Duff, a paederast, who destroys discipline by taking young lovers among his forecastlemen. Another of the captains is a tyrant, Captain Thomas who, unlike Aubrey, values spit and polish more than efficiency in battle, and indiscriminately flogs his crewmen. These two captains and their crews soon find themselves at odds, threatening the squadron's efficiency. The Ringle makes it safely to Corunna in Galicia where Stephen sees off his wards and deposits his considerable amounts of gold. The Ringle rendezvouses with the at the Berlings off Cape Finisterre, and they make their way to the Gulf of Guinea in West Africa, with the crews practising hard at lowering down boats. Stephen survives a near fatal bout of Yellow Fever contracted while traipsing around the swamplands of West Africa in his usual search for rare birds and animals, a quest in which he is ably assisted in Freetown by the British colonial governor's wife, Christine Wood (née Hatherleigh), herself an esteemed naturalist and sister of one of Stephen's fellow members of the Royal Society. The squadron successfully disrupts the slave trade, saving over 5,000 slaves and having eight slaving ships condemned. Aubrey then hastens to meet the French squadron, commanded by the wily Commodore Esprit-Tranquil Maistral, south and east of the point the French are expected to reach (West Cork). Jack informs his captains of his plan of attack and the Bellona attacks the French pennant-ship, with the Thames and Stately attacking the other French two-decker. The first strikes on a rocky shelf and surrenders; the second badly mauls the Stately (Duff loses a leg) and flees eastwards. The four French troop carriers and one frigate are also captured (one frigate also escapes), aided by the Royal Oak and Warwick, who join the scene of battle. Maturin finds as the novel closes that the Duke of Habachtsthal has committed suicide. This is possibly due to the threat of trial for treason after being identified by Clarissa Oakes and following extensive investigation carried out by Pratt, a former Bow Street Runner employed by Maturin and Sir Joseph Blaine. Stephen is also happily reunited once more with Diana, who happens to be living near that part of the Irish coast with one of her first husband's uncles.