Within the ruins of this world, there two inhabited neighborhoods, the southwestern town and Ameyoko in the northeast. The city has a network of subway tunnels which had once been used to transport passengers across the city.
This world was once a thriving metropolis until Su-Zaku and his minions invaded, laying waste to much of the city. Su-Zaku himself attacked people who traveled on the streets, and was protected by a barrier which repelled attacks and even revived him if he were slain by someone with efficient attack power or was equipped with the Saw weapon.
A gang of bikers in the southwest town, led by So-Cho was plotting to create a device to erase Su-Zaku's barrier. The party meets with So-Cho and the gang, introduced by his sister Sayaka. They collect the components for the device, Eraser 99. So-cho died in the process of collecting the plutonium. Just after Eraser 99 was assembled, Su-Zaku and his minions attacked the southwest town and kidnapped Sayaka. The party follows him to the Shinjuku Building, where they descend through the building's subway station and confront Su-Zaku on top of a subwat car, killing the fiend. Afterwards, at So-Cho's grave site, Sayaka gives the party the Red Sphere.