As the apocalypse approaches, humans invent "replacement metabolism" - giving up one sense in exchange for an equal amount of body energy supply.
The rich give up their sense of pain in exchange for a hundred years of life, while the poor sell their sense of taste just for a full meal. The city was divided into the "sensual aristocracy" and the "incomplete class". Sensory exchanges were built one after another, and cruel transactions between souls and bodies were performed every day.
Gu Huaixu is the top appraiser of the exchange. He is born with the ability of "sensory integration" and can clearly understand every inch of emptiness when others lose their senses. Until one day, a "zero-sense old man" who had stripped away all his senses and relied solely on machines to survive was secretly sent underground. He used his last mental power to convey the truth to Gu Huaixu: every replacement was draining the earth's biological energy field in reverse. Plants are dying in patches, and the land is deserting at an accelerated pace. What humans are devouring is not external energy at all, but the life of the planet itself.
The old man is the original inventor. He gave up everything just to sneak into the system to find the termination password. Now the password has been passed to Gu Huaixu, but there is only one way to activate it: he himself must first give up at least one of his senses.
Replace it with what? Pain? Taste? Or... The "unity" he relies on for survival?
When he cut off his last human barrier with his own hands, he saw clearly the appetite that had been eaten by all mankind for twenty-three years - it never intended to stop.
