This is book 20 of the "Aubrey-Maturin" series.

This note contains spoilers for the book.

Kind of the end.

They get to Chile, but things are somewhat changed, with multiple local juntas contending for control. Jack is doing some good work training a Chilean navy, and thinks very highly of the midshipmen he's training for that. He also pull off a very successful cutting-out expedition against Peru, getting their heaviest frigate before it can be used against Chile.

Jack has also taken on board as a midshipman the illegitimate son of the Duke of Clarenc (probably the next king). Luckily (well, Jack did examine the boy before agreeing to take him), he's shaping up into a good seaman and a fine navigator and officer, and he plays a valiant part in the cutting out expecition.

The Chilean authorities, such as they are, treat the Surprise somewhat shabbily, withholding owed prize money and causing endless delay in the prize courts. Jack gives them an ultimatum, which is only partially met.

And just as that ultimatum comes due, unmet, Jack gets orders to proceed to the River Plate and meet a squadron that he will then take to the South African station and hoist his penant, blue at the mizzen, as a rear admiral. Jack has been injured, but this perks him up remarkably. Preserving Chilean independence is important, and the order includes a provision for sending the Dukes son home to pass for lieutenant immediately, so political interest seems to be in play as wall. (The dispatch on the raid, and the orders, travel to and fro very quickly due to some careful management on Stephen's part, using conduits established for intelligence data.)

Meanwhile, Stephen is still courting Christine, governor Wood's widow. He proposed in Africa, and she is doubtful, having so far as I can tell been sexually incompatible with her previous husband, who may have been only partially functional. Stephen is interested in sex, but would happily marry her and skip that part if necessary, but he hasn't quite explained that. Also, they are both quite well-to-do, so there's no real need to formalize any relationship anyway.

This was the last book O'Brian completed. The three chapters he'd written of the next have been published, titled 21, and I'm going on to read them (for the first time; this reread of the rest was in preparation for finally reading the last bit). But three chapters isn't very much. It does make it entirely clear that O'Brian wasn't done with the story, anyway.