Action in Admiral Rodney's dramatic Moonlight Battle of 1780, when Cyclops' capture of the Santa Teresa plays a decisive part, is the start of Nathaniel Drinkwater's life at sea. HMS Cyclops is involved in pursuing American privateers who are a danger to British trade and Drinkwater finds himself part of a prize crew when initiative and courage in a critical situation enable him to survive a dangerous encounter. When the frigate is detached on special service to the swamps of South Carolina, grim actions are fought at sea and by a detachment of the ship's company on land, resulting in violent deaths before Cyclops arrives in New York in 1781 and is sent back to Spithead with the news of Lord Cornwallis' surrender at Yorktown. Through his experiences both in action and in the hard life on Cyclops, Drinkwater matures and gains the ability to stand up against the tyranny of the midshipmen's mess and the sinister and evil influence of the senior midshipman, Morris. In overcoming his difficulties he is sustained by his growing love for Elizabeth and the contrast of home life with the brutality of naval service.