Gregor The Overlander is a story about A young boy and his baby sister, who are residents of New York City, find that in their apartment complex's laundry is an entrance to the Underland; a world containing no natural light, filled with humans with translucent skin, giant bats, snails, moles, scorpions, cockroaches, rats, lizards, mice, ants, snakes, fireflies, and spiders which they call fliers, slimers, diggers, stingers, crawlers, gnawers, hissers, nibblers, cutters, twisters, shiners, and spinners, respectively, and more unusual things you would not normally come in contact with in the Overland. Gregor does everything he can to get himself and his sister home... but when the humans of the Underland reveal that Gregor is the "Warrior" foretold in prophecy, Gregor goes on an epic journey to get hold the Underland's human inhabitants and their world as they know it.