Admiral Pellew arrives and gives Hornblower his next mission: HMS Grasshopper, commanded by old friend Captain Bracegirdle, has gone missing while on patrol off the coast of France.
On a stormy night, Hotspur rescues the passengers of a small boat in danger of sinking off the coast of France, including a man claiming to be Swiss and his American wife.
Back in England, Pellew has received orders from the Admiralty to find a young couple, a Frenchman and the daughter of a wealthy American merchant, who are somewhere at sea near France.
Back in England, Pellew learns from a diplomatic service official that Napoleon's brother and his heiress wife are aboard Hotspur.
Hornblower, Bracegirdle, and their reconnaissance party discover quantities of French maritime cannons hidden ashore but cannot discern the reason.
Hornblower reports to Pellew, who informs him that the diplomatic service has quarantined Hotspur to keep Jérôme-Napoléon's presence in England a secret: no one can disembark or board, captain included.
This leads to a fistfight during which Doughty accidentally strikes Midshipman Orrock, an offense punishable by death according to the Articles of War.
The next day Hornblower and Bush go ashore and discover that the cannons they found earlier had been removed from three frigates anchored in a bay, freeing up enough space to transport 1,000 soldiers each.
Hornblower summons Doughty to the captain's quarters, hints that Liberty is close enough for him to reach by swimming, then leaves him unguarded.