Wolves howling. That's all Ella can hear, even through the obsidian walls of her grandmother's mansion. It's as if the wolves are calling to her, begging her for help. Do her cousins, Rowan and Jack, hear it too?

Grandmother warns that the Overworld is full of deadly mobs, but Ella knows she has to go. As she braves the Overworld, she discovers her special gift--her ability to communicate with animals. And she gathers clues about the mother she never knew. But as Ella battles to save the wolves, she realizes that she is in grave danger, too.

Soon, the cousins will not only learn what happened to their parents, but also learn of the danger facing them all. They'll need to call on their special gifts--and their animal friends--to fight back.