One by one the kings of Braetan kneel before King Arthur under a banner of peace.

Hwyfar, eldest daughter of King Leodegraunce and famed libertine of Carelon, has returned to Avillion to find her father ruined by madness and a usurper poised to take the throne. Reluctantly she takes the mantle of Queen Regent to protect her kingdom, but she'll need an army—which King Arthur pledges to send her, providing she marries one of his knights and surrenders the crown.

Arthur's forces arrive under the command of Gawain of Orkney, who Hwyfar remembers as a brute; but she comes to realise he is not the man she thought he was, and finds herself irresistibly drawn to him. But Arthur has plans for her, and has commanded Gawain to keep well away—and in Arthur's court, without the King's blessing, love is treason.

Hwyfar and Gawain must navigate both a world of ancient forests and corrupt magic, and the political machinations of two courts, if they have any hope of escaping Arthur's ever-tightening grasp.