Born and raised on Circe, the planet with a mind, Borto Claibrook-Merjolaine is the only man of his generation to become a warrior. As he learns combat skills on the neighbouring planet of First Home, his mentor detects a dark creature hidden deep inside Borto's personality. Coming from Circe's own shadow, the being adds extra strength to Borto's normal Circean abilities. Also living on First Home, Borto's sister, Tethyn, realises that she must go to find the source of a great danger which is threatening both Circe and First Home. Another planet farther away in the galaxy has learned about First Home and is preparing an invasion force. Against the wishes of her beloved man Lewis, Tethyn asks his greatest adversary, Darland Courvenier, to take her to meet a man from the enemy planet so that Circe can learn about the advancing peril and prepare to defeat it. Circe is also in danger from First Home. Darland and his close friend and lieutenant, Vaire, have begun to realise that Circe is a very special planet, possessing strange powers. They want to learn her secrets. Vaire goes to Circe to discover what he can about her, at the same time drawing Tethyn's best friend, Rayanna, the woman he has come to deeply desire, unwillingly to him. Returning briefly to his home planet, Borto finds that contraband weapons have been hidden on her surface, infecting the planet with the negative force they carry. As he helps to defeat the arms smugglers, the thing that Borto has been dreading happens, and his loyalty to his beloved planet is put to its greatest test.