The film is set in 1903, in a world where steam power has become the dominant source of energy. The story takes place in London, which is depicted as a sprawling metropolis with towering steam-powered factories, intricate networks of pipes and gears, and a complex system of social hierarchy. The city's architecture and technology are meticulously detailed, drawing inspiration from the Industrial Revolution and the works of inventors like Charles Babbage and Isambard Kingdom Brunel. Otomo's vision of a steam-powered London is both nostalgic and futuristic, evoking a sense of wonder and curiosity.