Hornblower is given command of a detail going ashore to Oran, on the North African coast, to buy grain and cattle for the fleet. When they discover the town is infected with black plague Hornblower is appointed captain of the Caroline, a transport schooner, and spends three weeks of mandatory quarantine at sea with the rations. After returning to the HMS Indefatigable at Gibraltar, Hornblower attempts his Lieutenants exam. He is failing until a fire ship sails into the harbor. Hornblower and his friend Foster board the ship and steer it clear of the fleet. Admiral Pellew remarks on Hornblower's courage and he is allowed to keep his rank until the next exam.