In a world where girls grow up to be housewives and mothers, Marion Ackerman longs to be a sailor. But as her family falls into poverty, she is forced to make a choice - marry the man who tried to kill her, or run away on the MARGARET ROSE, a ship of His Majesty's Navy. Will Marion give way to the pressure of society, or will she answer freedom's call and be able to survive the perilous voyage?