When eleven-year-old Gregor follows his little sister down a laundry chute, he hurtles into Underland, a world deep beneath New York City.

There, humans live uneasily alongside giant spiders, vast cockroaches, huge bats and some appalling rats, and their fragile peace is about to fall apart. Gregor wants no part in their troubles. But when a strange prophecy reveals a role for him in the Underland's uncertain future, he knows there is no turning back.