Stranded in Malta, Captain Jack Aubrey and surgeon Stephen Maturin must be careful, for the salons and dockyards are infested with Napoleon’s spies, and there is a traitor in the British intelligence network. This installment of Patrick O’Brian’s “20-volume masterpiece” (Christopher Hitchens) takes Aubrey and Maturin sailing on the pirate-plagued waters of the Red Sea, trudging over the Sinai Peninsula and even the depths of the sea floor in their efforts to stay one step ahead of the treachery afoot.