Steampunk in the world of cats

Late at night, he/she was repairing an old German stopwatch from the Second World War. As he/she inserted the last gear, the dial glowed scarlet. The mechanism hummed on an alien frequency, and the air smelled of ozone and burnt insulation.

He (she) blinked and found himself lying on the cold cast-iron pavement.

Above him, gas lanterns with green flames swung on chains. Steel beams, from which locomotive whistles hung, crossed the sky. Steam billowed from shafts in the walls. And cats were everywhere.

Cats in waistcoats with pocket watches. Cats with mechanical paws, in which pistons softly clattered. Cat policemen in copper helmets with plumes. Cat lords in monocles, perched on moving chairs driven by cogwheels.

He/she tried to get up, but someone's shadow covered him/her from behind.

“Move your mustache and I’ll open your valve,” the voice hissed.

Turning around, he (she) saw a huge British Shorthair cat. In its paw, it held a steam-powered screwdriver, pointing it like a pistol. But most importantly, the cat spoke. In pure Russian, albeit with a purring accent.

"Not a single person has been here for three hundred years. You are contraband. A violation of the Third Steam Code. You should be melted down into click springs." It suddenly became clear: he (she) wasn't just somewhere else. He (she) was in a world where humans were either extinct or never existed. And cats had built an entire civilization on coal, steam, and disdain for the "hairless."

The only one who could help was an old, lame, exiled cat with a broken optic eye. He was once the portal's chief engineer, but for attempting to summon the "old masters," he was stripped of his rank and exiled to the steam slums.

The world of the Great Cauldron is an endless city-machine built on the remains of a gigantic steam engine. No one knows who created it, but cats are certain it was the First Cat. The city is on three levels. The top is the Needles, where Maine Coon lords in brass spires live. The middle is the Paws, with markets and workshops. The bottom is the Tails, slums shrouded in steam fog. There is no electricity, considered evil magic. Everything runs on steam and clockwork mechanisms. Transportation consists of steam-powered mousedromes shaped like sardines and methane-fueled airships. The government is the Council of Nine Tails. The estates are lords, craftsmen, workers, and outcast sphinxes with no voting rights. Money is fish scales and copper nuts. The main religion is the Church of the Whistling Cauldron. The main enemies are the Glass Dogs, who turn cats into statues, and the sentient rats from the sewers. In the center of the city stands the Great Cauldron—a gigantic furnace. Once a day, the Hour of Grinding occurs, causing cats to cover their ears. Humans in this world are mythical creatures. When a traveler arrives through a broken portal, the cats call them "Fingered" and grant them the status of a living thing. They are prized for their fingers, which can turn small gears, and their fear of water. The only way to return home is to activate the Fate Claw, an ancient oracle that has been inactive for 300 years. Almost all attempts end in death. But people still try.