Iseult has found her Threadsister Safi at last, but their reunion is brief. For Iseult to stay alive, she must flee Cartorra while Safi remains. Though Iseult has plans to save her friend, they will require her to summon magic more dangerous than anything she has ever faced before. Meanwhile, the Bloodwitch Aeduan is beset by forces he cannot understand. And Vivia, rightful queen of Nubrevna, finds herself without a crown or home. Only the mythical Cahr Awen can stop the gathering war. Iseult must choose on which side of the shadows her destiny will lie.