Gregor the Overlander

When eleven-year-old Gregor and his two-year-old sister fall through a grate in their apartment building's laundry room, they land in the Underland, a dark underground world beneath New York City. There, they encounter talking bats, rats, cockroaches, and spiders who are engaged in a fierce war. Gregor embarks on a dangerous quest to fulfill an ancient prophecy and find his missing father.