Castor has always been a stray, prowling with his pack in the back alleys of Lion's Head. That is, until the day that he's captured and taken to a dark laboratory full of terrifying creatures. They're called Unnaturals, and they're made to fight.
Soon Castor is transformed from a mutt into a powerful beast with huge eagle wings—and he's thrust into the fighting ring. He knows he'll need all of his courage to survive. But it will take unexpected human and animal allies and something even more than courage for him to save the Unnaturals....
K-07M0 has never had a name. As a fox-bat, she has lived her entire life silently hiding from the other hybrids and the scientists who created her…until the day a new animal gives her the name Kozmo and they help each other escape the underground lab.
In the outside world Kozmo meets a pack of hybrids just like her, led by a feisty eagle-dog named Castor. But Castor and his pack are being viciously pursued, and Kozmo is forced to do something she's never done before: trust others to survive. Kozmo will discover that Castor and his friends have unexpected human allies but can they uncover the truth about why the Unnaturals were created together?