In 1807, during the Napoleonic Wars, British Capt. Horatio Hornblower sets sail from England on the H.M.S. Lydia , carrying a cargo of muskets and ammunition. Known only to Hornblower, the Lydia 's mission is to deliver the arms to a group of Central American rebels led by Don Julian Alvarado, hoping that they will distract French ally Spain from an attack on England. Hornblower is a strict disciplinarian and brooks no disrespect from his crew, but his scrupulous fairness has won the love and admiration of the men who sail with him. Before the Lydia reaches her destination, the ship is becalmed and the men become ill from scurvy. Although Gundarson, the ship's surgeon, begs Hornblower to land and take on fresh supplies, Hornblower refuses to jeopardize his mission. Eventually, as Hornblower had predicted, the wind returns, and the ship reaches its destination, where Hornblower meets with Alvarado, called El Supremo by his ragtag followers. Although shocked by the deranged Alvarado's behavior, Hornblower delivers the weapons to him. When the Spanish ship Natividad anchors nearby, Hornblower and his crew board the ship at night, and after a brief fight, the Spanish surrender. After placing the Spanish officers in the Lydia 's dungeon to save them from being killed by Alvarado, Hornblower gives the ship and its cargo to the rebels. Later, off the coast of Panama, the Lydia encounters a Spanish ship flying a white flag and learns that Spain and England are now allied against Napoleon. On board the Spanish ship are the Duke of Wellington's sister, Lady Barbara Wellesley, and her maid Hebe, who are escaping a yellow fever epidemic. With great reluctance, Hornblower agrees to convey the women to England, but not before he recaptures the Natividad . This time, there are many casualties and the Natividad is completely destroyed. During the fighting, Barbara cares for the wounded and wins Hornblower's respect. As the Lydia continues her return journey, Barbara becomes ill with fever. Hornblower nurses the sick woman himself because he fears a yellow fever epidemic on board. Barbara's illness proves to be the less serious swamp fever, and she recovers completely. Soon, Barbara and Hornblower have fallen in love. Although Barbara is engaged to Rear Adm. Sir Rodney Leighton, she reveals her feelings to Hornblower, who discloses that he is married. On the Lydia 's return to England, the crew is greeted by a jealous Leighton, who chastises Hornblower for failing to capture the Natividad . When Hornblower arrives at home, he learns that his wife has died giving birth to his son. Barbara's wedding to Leighton takes place as planned and in due course, Hornblower is assigned to a ship under Leighton's command. Defying Leighton's orders, Hornblower captures a French ship, and then deduces the location of a small fleet of French ships, which he manages to disable. However, as Hornblower leaves the cove, his own ship is demolished by the French land forces, and his crew swims ashore, where they are captured. Hornblower and the badly wounded Lt. William Bush, accompanied by seaman Quist, are taken to Paris to be tried as pirates. On the way, the men manage to escape. After disguising themselves as Dutch soldiers, they discover a ship carrying English prisoners. With the prisoners' help, Hornblower, Bush and Quist take over the ship and sail for England. Later, Quist tells Hornblower that he will open a pub with his prize money, which he intends to name in Hornblower's honor, and Bush is promoted to captain. When Hornblower returns home to visit his son, he is surprised by a visit from the widowed Barbara, whom he heartily embraces.