Carved from the rugged Chiricahua Mountains, the intimidating spire, Thunder Peak, slashes the sky, haunting the southern reaches of the Arizona Territory. Staked in the darkest corner of Thunder Peak’s shadow lies the Tamm Ranch and Orchard, run by Civil War veteran Jonas Tamm. Jonas lives with his adopted daughter Casey and knows more about the mysterious history of the canyon they call home than anyone. When Casey rescues a hornless, juvenile unicorn from a bloodthirsty wolfpack, Jonas realizes that it's time to tell her those secrets. Secrets that will cast them in a race against time to get the unicorn home before he loses his horn forever- and array them against an ancient predator from a distant realm. A merciless nightmare of fang and claw who also wants to get home. A destination that lies at the end of but one path: The destruction of Casey and her beloved unicorn.