The Innocent Sleep by Seanan McGuire

The 18th novel of the Hugo-nominated, bestselling October Daye urban fantasy series.

For one bright, shining moment, Tybalt, King of Cats, had everything he had ever wanted. He was soon to set his crown aside; he had married the woman he loved; he was going to be a father. After centuries of searching for a family of his own, he had finally found a way to construct the life of his dreams, and was looking forward to a period of peace—or at least as much peace as is ever in the offing for the husband of a hero.

Alas for Tybalt and his domestic aspirations, fate—and Titania—had other ideas. His perfect world had been complete for only a moment when it was ripped away, to be replaced by hers. Titania, Faerie’s Summer Queen, Mother of Illusions and enemy of so many he holds dear, has seized control of the Kingdom, remaking it in her own image. An image which does not include meddlesome shapeshifters getting in her way. Tybalt quickly finds himself banished from her reality, along with the Undersea and the rest of the Court of Cats.

To protect his people and his future, Tybalt must find the woman he loves in a world designed to keep her from him, convince her that he’s not a stranger trying to ruin her life for no apparent reason, and get her to unmake the illusion she’s been firmly enmeshed in. And he’ll have to do it all while she doesn’t know him, and every unrecognizing look is a knife to his heart.

For Tybalt, King of Cats, the happily ever after was just the beginning.