HMS Rover, a thirty-six-gun sailing frigate with a crew of four hundred, sets sail for West Africa in search of slave traders. Flag-lieutenant Onslow is looking forward to doing his bit, not to mention adventures and prize money. When Commodore Windham, in command of the West Africa squadron, comes on board, he brings his beautiful daughter with him. As flag-lieutenant it is Onslow's duty to assist the commodore in every way, including looking after his daughter, a duty that soon blossoms into rather more. The perils of storms, disease and battles with slavers soon put the crew of HMS Rover to the test.