We open with the king pleading with the wizard Atrix Wolfe, to work magic that will enable him to overcome another king. Atrix makes it clear that this is Not A Good Thing and Not What Wizards Do. But he keeps up the pressure. Meanwhile Saro, the daughter of the Queen of the Wood, and her father, owing to their drop of mortal blood, watch the scene curiously. Atrix, finally infuriated, weaves together a terrible spell, and unleashes a dark rider on the battlefield.
That was the prologue. The story picks up years later, with Tanis, the son of the king who died on the battlefield, who was born that very day, arguing with another student of wizardry about which king was responsible. Given that one died, and the other was driven from the field, there's no good argument for either except that the other one wouldn't have. But Tanis is summoned home. He goes up on the mountain where he catches a glimpse of the famous White Wolf, Atrix Wolfe himself, and grabs a book from the library, and goes.
Meanwhile, there's a mute girl who works in his brother's castle, as a scullery maid. Her name is Saro.
And Atrix Wolfe is plagued by dreams that send him back to the kingdom.
In McKillip's lyric prose, we get dreams with messages, an enchanted wood, a haunted keep, a magical misleading book, visions in a full cauldron, brotherly love, secrets, and the need to undo what was done.