In his second adventure, eleven-year-old Gregor returns to the world beneath New York City to rescue his kidnapped sister, Boots, and fulfill a prophecy that will restore peace to the people, bats, rats, cockroaches, and spiders who populate the underworld.
Eleven-year-old Gregor and his younger sister, Boots, return to the Underworld beneath New York City to find the cure for a terrible plague that threatens the life of their mother, as well as the lives of the people, bats, and rats who populate the underworld.
Twelve-year-old Gregor returns to the world beneath New York City, where he joins forces with Princess Lexa and Ripred the rat to defend the Underlanders and the Nibblers from the army led by the adolescent rat king, the Bane.