As he travels back to England for his next assignment (and his promised elevation to post rank), he is asked to participate in the court martial of Hotspur's new captain.

He arrives at the same time as the disappointing news that the French fleet under Admiral Pierre-Charles Villeneuve has escaped into Ferrol, Spain after an indecisive engagement.

He proposes sending agents to Spain, posing as messengers, to deliver false orders from Napoleon Bonaparte to Villeneuve.

This plan has been made possible because the papers captured by Hornblower include a routine letter from Napoleon, whose form can be copied.

The Reverent Doctor Claudius - a disgraced clergyman and expert forger - is recruited to create the false letter from Napoleon.