Inui tells Saki that it was Kiroumaru who rescued him after he collapsed, but was subsequently taken prisoner. Saki receives a package and a letter from her mother in which she learns of an ancient weapon called the "Psychobuster", devised by normal humans to kill psychics. Saki and Satoru visit the imprisoned Kiroumaru, who offers them his help in finding the weapon's location, and the trio depart with Inui to the desert ruins of Tokyo to search for the Psychobuster. However, they fail to bypass the Monster Rats' blockades undetected and soon after arriving in the dangerous wasteland, they learn Yakomaru, his army, and the Ogre have followed them there.