At the end of the 21st century, a rare disease called “Cagaster” broke out, turning humans into huge insects. Two-thirds of the earth‘s population was devoured by these insects before humanity made a decision: they must exterminate the infected people. In the year 2125 – thirty years after the discovery of Cagaster – at the edge of the desert close to the “cage” of the insects, a young pest exterminator named Kidou finds a man close to death due to the wounds by insects. The man entrusts his daughter Ilie to Kidou and asks him to search for the girl‘s mother…