In the “City of Rain,” where Mobots live, each robot must carry an umbrella to protect themselves from the rain. If their metal bodies are exposed to moisture, they begin to rust and break down. Despite their efforts, the umbrellas can’t fully shield them from the dampness. This forces the Mobots to work endlessly, saving up money to buy new parts just to stay alive. But not all Mobots can afford it. The wealthy control everything, while the lower-class Mobots are trapped in a cycle of working until they can no longer function.