In this haze-shrouded near-future city, some people have mutated due to long-term exposure to special pollutants, and a very small number of people have awakened "grey matter powers" that have nothing to do with combat effectiveness but resonate subtly with the urban environment. The protagonist Li Qi is an abandoned pipe cleaner who can weakly sense the "emotion" and "pain" of the city. When he senses unusually violent and concentrated "painful" fluctuations coming from the city's underground pipe network system, accompanied by disappearances, he must rely on this meager ability to go deep into the darkest bottom of the city and expose the devouring mouths that have been deliberately forgotten under the glorious order.
