The lifters

"Twelve-year-old Granite "Gran" Flowerpetal has just moved from the sunny coast to a hilly inland town full of trouble and mystery. He feels unheard at home and invisible at school--and then there's the issue of the many buildings in town collapsing into the earth. What can be done? One person, Gran's intriguing but difficult-to-please classmate, Catalina Catalan, knows what to do. But she avoids Gran like the plague. Will she reveal what happens underground? Will she tell Gran about the Hollows? The Lifters? And how the town, and the world, might be saved?"--Dust jacket.