After obtaining the addiction cure, Xu Yang followed Guan Wancang to visit Sally.
The most important part of this trip was to try to free Sally from her stamp addiction and, secondly, to understand the current living conditions of the Ratmen.
They did not take the usual highways and aerial passages but rather the secret tunnels the Ratmen had burrowed throughout Aizu City, collectively known as the "Great Maze" or "Rat Paths," connecting ventilation shafts, vertical wells, underground structures, sewers, abandoned subways, and parking lots, which had already turned Aizu City into a sieve.
The Ratmen racked their brains to survive, but they were unwelcome; even the local black market and gangs were reluctant to come into contact with them, leaving them in a particularly isolated situation. To them, human society was a distant, isolated island.
