Sleep No More by Seanan McGuire

The 17th novel of the Hugo-nominated, New York Times bestselling October Daye urban fantasy series.

October is very happy with her life as the second daughter of her pureblood parents, Amandine and Simon Torquill. Born to be the changeling handmaid to her beloved sister August, she spends her days working in her family’s tower, serving as August’s companion, and waiting for the day when her sister sets up a household of her own. Everything is right in October’s Faerie. Everything is perfect.

Everything is a lie.

October has been pulled from her own reality and thrown into a twisted reinterpretation of Faerie where nothing is as it should be and everything has been distorted to support Titania’s ideals. Bound by the Summer Queen’s magic and thrust into a world turned upside down, October has no way of knowing who she can trust, where she can turn, or even who she really is. As strangers who claim to know her begin to appear and the edges of Titania’s paradise begin to unravel, Toby will have to decide whether she can risk everything she knows based on only their stories of another world.

But first she’ll have to survive this one, as Titania demonstrates why she needed to be banished in the first place—and this time, much more than Toby’s own life is at stake.