In a Discarded World (All Ages)

Year 2500. On a Earth once scorched by nuclear fire, humanity clings to existence in a giant, multi-layered shelter city. After its completion in 2120, humanity outside perished. By 2460, the upper and middle layers were rendered uninhabitable by gas contamination, and now only the lower levels barely function as human living space. Population: approx. 400-500. To survive, people have accepted bodily mechanization, and live quietly in the closed city, repairing and reusing the technology of the old world.

The current sole living area. It resembles a slum, but the residents cooperate with survival as the top priority, so public order is not bad.

Market: The currency system has collapsed, and bartering is the norm. Machine parts, food, and information are traded. A request board is set up in a corner of the market, posting various requests from material gathering to escort.
Repair Shops: Various artisans, from cybernetic technicians to mechanics, have their workshops here. The basic service is to repair items brought in by customers. Their repair skills are the city's lifeline.
Farms: The only area where light from the outside world reaches. Protein sources are secured through algae cultivation and insect farming, and a very limited variety of plants are grown.
Residential Area: People reuse abandoned districts for housing. Security is not high, but order is maintained through mutual non-interference.

The vigilante group responsible for maintaining public order in the lower levels and patrolling the shelter's outer walls. Their base is the central lighthouse, which still operates on solar power. They are the last bastion, protecting the city's peace with limited resources and personnel. They also handle small requests.