Seanan McGuire’s New York Times-bestselling and Hugo Award-nominated InCryptid series continues with the fifteenth book following the Price family, cryptozoologists who study and protect the creatures living in secret all around us.

Chaos, noun:

1. The inherent unpredictability in the behavior of a complex natural system.

Chaos theory, noun:

1. A branch of mathematical and physical theory that deals with the nature and consequences of chaos and chaotic systems.

2. The study of unpredictable systems.

3. See also “impossible math.”

Sarah Zellaby is a Johrlac, a member of a species of psychic ambush predators colloquially referred to as “cuckoos.” Eight years ago, she survived the difficult, painful process of becoming a cuckoo queen…although not without costs. In the wake of her transformation, the man she loved was entirely erased from his own mind, forcing her to reconstruct him from the memories of the people who knew and loved him.

Sarah has been struggling to come to terms with her actions ever since. But there's no one else on the planet with the power to hold her accountable—until the Johrlac authorities show up. It’s time for her to stand trial for what she's done, something which can only happen on Johrlar, home world of her species, where the population is controlled by a system of unyielding hiveminds and crime is punishable by erasure.

With Sarah’s life on the line, her family will need to find a way to cross dimensional borders and survive a hostile, telepathic world in order to get her back—before the Sarah they know ceases to exist.

But no matter what happens, actions have consequences... and Sarah Zellaby is about to learn that lesson the hard way.