While surviving life-threatening adventures at sea, Captain Jack Aubrey and Dr. Stephen Maturin find life on land to be even more perilous. Aubrey has dimmed his prospects of an admiralty by his erratic voting in Parliament. He is on even worse terms with his wife, Sophie, when his mother-in-law ferrets out a trove of old personal letters. Fortunately, Maturin brings news that the Chileans need the two seafaring friends to train their navy.