Freshly back from a year in the Indian Ocean, it is not long before Alexander Clay and the crew of the Titan are in action once more. This time they are sent on a secret mission across the Channel. Amongst the forests and marshes of Southern Brittany, a Royalist rebellion is building and the Government at home is keen to support it. But as the uprising grows, Clay finds himself being drawn into a world of deception, intrigue and treachery. Who is the charismatic rebel leader, Count D'Arzon, and what is the secretive Major Fraser really up to? Meanwhile the settled community of the frigate's lower deck is disturbed by the arrival of a new recruit who appears to have strange mystical powers.