The 16th volume in the popular high-seas nautical adventure series featuring naval hero Thomas Kydd. The greatest naval trial in the Georgian period is underway at Portsmouth with the court-martial of Sir Home Popham, Captain Sir Thomas Kydd's commanding officer in the doomed occupation of Buenos Aires. Kydd has sympathy for Popham's unauthorized action but his support for his former commander leaves him athwart some very influential people in the Admiralty.

With his frigate L'Aurore unfit for sea, Kydd is given a new commission that his rivals hope will destroy his career. The Tyger's have recently mutinied, but instead of dispersing her company around the fleet as is customary, the ship is pressed into immediate service in the North Sea and Kydd faces a crew still under some malign influence. Enemies aboard and on the high seas are just the start of the problem. Soon he will have to take his untested and untrustworthy crew into the Baltic, where they will find themselves entangled with Napoleon's invasion of Prussia. The stakes are desperate, the task seemingly impossible, and the French implacable. The only way for Kydd to avoid disgrace is to gamble his reputation and crew on a crazy mission to snatch a Prussian division out of the jaws of Napoleon's advancing army. Will he return home once more a hero or face a court-martial himself?