Books in the The Underland Chronicles series

Spies have reported the sighting of a Rat King in the Underland. But when Gregor eventually comes face to face with the Rat King, he finds he is unable to kill him. Gregor's heart tells him he's making the right decision. Will it be one he lives to regret?

Gregor and Boots must return to the Underland to help ward off a plague. It is spreading fast, and when it claims one of Gregor's family, he begins to truly understand his role in the Prophecy of Blood. Gregor must summon all his power to end the biological warfare that threatens the fate of every warmblooded creature.

Everyone in the Underland has been taking great pains to keep The Prophecy of Time from Gregor. Gregor knows it must say somethin awful but he never imagined just how awful: it calls for the warior's death. Now, with an army of rats approaching, and his mum and sister still in Regalia, Gregor the warrior must gather up his courage...

When eleven-year-old Gregor falls through a grate in the laundry room of his apartment building, he hurtles into the dark Underland, where spiders, rats and giant cockroaches coexist uneasily with humans. This world is on the brink of war, and Gregor's arrival is no accident. Gregor has a vital role to play in the Underland's uncertain future.

It's only a few months since Gregor and Boots returned from the Underland. Now Gregor must return to fulfill his role as the warrior who is key to the Underlanders' survival. Accompanied by his now-talkative little sister Boots, still considered the honorary "princess," Gregor joins forces with another princess to defend the Underlanders.