Look. Madeline. You've lost your soul. You've lost your freedom. You've lost a bit of your sister. What else could go wrong?

Catlin and Madeline are extraordinary sisters, living extraordinary lives - in a place that seems entirely ordinary, but which in fact seethes with secrets, both sacred and sinister. Ballyfran is a village where, for centuries, people who are not quite human have gathered. Catlin has already fallen foul of one such creature - a dark, vicious predator who almost killed her - and only Madeline giving up a part of her own soul was able to bring Catlin back from the brink of death.

Now, the girls are making their strange new lives: Catlin, haunted by what happened to her, is isolated and bereft; Madeline is learning ancient magics under the tutelage of local wise woman Mamo. Learning that magic isn't mindfulness and hats. It's work - hard work. And Madeline knows she has to keep watch. On her sister. On the things that happen. Notice things before they start to happen. And before long, they do ...