Horatio joins the Royal Navy at seventeen, a bit old to start a Naval career. Although he started out behind the other midshipmen he has a good mind for navigation. What he doesn't take to is the bullying from one particularly nasty chap. One thing leads to another, and that leads to a duel.
Having progressed in his studies, the Captain puts Horatio up for the Lieutenant's exam. Meanwhile there is a problem with the Spanish tactic of lighting ships on fire and drifting them into the British Harbour!
Horatio is given command of a prize vessel. In the process of sailing it back to England, he runs into the Spanish fleet in the fog. He and his crew are sent to a Spanish prison, where he runs into a long lost friend, and makes a few escape attempts.
This episode finds Hornblower and the crew of HMS Indefatigable enlisted to help a Royalist General invade Republican France. A pompous French Colonel is more interested in introducing as many republicans as possible to his personal guillotine.
Horatio and company are serving under Captain Sawyer who was once a great leader but seems to be a bit unstable. He makes the life miserable for his lieutenants and midshipmen, but just when the situation seems helpless, the Captain has an accident.
With Captain Sawyer incapacitated, Lt. Buckland gets a long awaited chance to take command. After dealing with a slave revolt, Hornblower is put on trial.
Horatio confronts the different attitudes of Irishmen in the Royal Navy. One is openly antagonistic to the crown, one is loyal as Hornblower himself, and another seemingly loyal career officer reveals himself to have been working for Bonaparte all along. In contrast to the Irish, he must also deal with an Anti-Bonapartist Frenchman.
Shortly after getting married, Hornblower is sent out on a mission to find a British ship which was last seen of the coast of France, under the command of an old friend. While searching, the Hotspur picks up some unusual passengers.