What if nothing was as it seemed? What if the ground beneath your feet was not made of solid earth and stone but had been hollowed into hundreds of tunnels and passageways? What if there were mysterious forces in these tunnels, mere inches below you as you sit in class or eat a banana? What if it were up to just two kids to stop these forces? Twelve-year-old Gran Flowerpetal is about to find out... 9+ From the bestselling, Pulitzer-nominated author of "The Circle".