The entire existence of the Underland is in Gregor's hands, and time is running out.It’s been about a year since I said the words “fly high”. Now, with an army of rats approaching and his mum and sister still in Regalia, Gregor the warrior must gather up his courage to help defend Regalia and get his family home safely. Gregor knows it mustay something awful but he never imagined just how awful: it calls for the warrior's death. Everyone in the Underland has been taking great pains to keep The Prophecy of Time from Gregor. The stunning conclusion to the riveting Gregor the Overlander series. Accompanied by his now-talkative little sister Boots, still considered the honorary 'princess,' Gregor joins forces with another princess - 12-year-old Luxa - and Ripred the rat to defend the Underlanders and the vulnerable 'Nibblers,' or mice, from the rat army. Though Gregor's family receives frequent updates on her condition, they all know Gregor must return to fulfill his role as the warrior who is key to the Underlanders' survival. It's only a few months since Gregor and Boots returned from the Underland, leaving their mother behind to heal from the plague. Gregor must summon all his power to end the biological wrfare that threatens the fate of every warmblooded creature. 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 and Boots must return to the Underland to help ward off a plague. Gregor's heart tells him he's making the right decision.

Gregor eventualy comes face to face with the Rat King, and to his surprise, he finds he is unable to kill this creature. Recognizable by its tremendous size and snow-white coat, the Rat King is destined to bring a World War to the Underland. Spies have reported the sighting of a Rat King in the Underland, a character who has been legendary since the Middle Ages. Reluctantly, Gregor embarks on a dangerous adventure that will change both him and the Underland for ever

Gregor wants no part of it - until he realizes it's the only way to solve the mystery of his father's disappearance.

Gregor has a vital role to play in the Underlan's uncertain future. This world is on the brink of war, and Gregor's arrival is no accident. 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.

Gregor the overlander series book 6