I loved this and I needed to sit with it a while after I finished, before starting my next book. It's a body-horror/fairytale/love story between a 'mermaid' on land and her (plague) doctor, as they intervene in a morbid cult run by three false saints. It's like nothing I've read before (okay, maybe it's a bit T. Kingfisher-y - a good thing) and it's really beautifully written.