The Reverse of the Medal: Aubrey-Maturin Series, Book 11 (Unabridged‪)‬

Jack Aubrey returns from his duties protecting whalers off South America and is persuaded by a casual acquaintance to make investments in the City on the strength of supposedly certain information. This innocent decision ensnares him in the London criminal underground and in government espionage - the province of his friend Stephen Maturin. Is Aubrey's humiliation and the threatened ruin of his career a deliberate plot?