The book is set in the Yellow City, where magic has always been the purview of men, to the point that while men are called wizards if they have magic, the concept of women-who-do-magic is so incomprehensible to them that there is no simple word for it. But now the magic that men wielded is fading, to the point where the Yellow City is crying out for water and the wizards are unable to get the rain to fall.
At the same time, women are beginning to exhibit strange powers, unsettling to everyone around them, though now those women are disappearing one by one even as they come to know one another. In a society where only men have individual names and women are named in conjunction with them or have names that clearly delineate their status in society, where the fanatical followers of one of the Yellow City's gods are literally demanding blood and claiming to be all-powerful, it's even more dangerous than before to be a woman-who-does-magic.
I really enjoyed this book, the world of which has clearly been given immense amounts of thought by the author. Even the unsympathetic characters are well-drawn, the male characters just as real and three-dimensional as the women on whom the book (understandably) focusses, particularly Oryn who is the king of the Yellow City and who would much rather be reading poetry in his garden than fighting wars. I'm not sure if I would have bought this had I realised there is a sequel (Circle of the Moon) since I'm trying to avoid books that are part of series if I can, but I'm glad I did and am now adding the second book to my wishlist...