From the Newbery Award-winning author of The Eyes and the Impossible come the story of a mysterious underground world where nothing is as it seems.

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? What would it feel like to know the fate of an entire town rested on your shoulders? Twelve-year-old Gran Flowerpetal is about to find out.

When Gran's friend, the difficult-to-impress Catalina Catalan, presses a silver handle into a hillside and opens a doorway underground, Gran knows that she is extraordinary and brave. He will have no choice but to follow her and help save the town (and the known world). With luck on their side, and some discarded hockey sticks for good measure, they might just emerge as heroes.