This is a loophole in the rules of the ancient "contract plane" - under the rules of heaven, after the great demon comes to earth, he must establish a "support circle" in the mortal world: the mortals fed by the great demon will become living sacrifices, and the great demon will accumulate merit through cannibalism and blood to survive the tribulation. But Lin Zhao, the white snake, never thought about cannibalism in the first place. She just used the identity of a fox demon to sneak into this demon town, and planned to leave after three years. As a result, she accidentally fed Gu Nanxun, the poorest local mortal detective, triggering an ancient contract: she became his "contract demon". Every time he ate the food she fed, he would unknowingly extract 30% of her cultivation level, and she would also be rewarded with a piece of cultivation level by heaven for the act of "giving food". The more frequently she feeds him, the more stable his life soul is, and the stronger she becomes. Then the most ridiculous situation appeared - a thousand-year-old snake demon chased a mortal man every day to feed him sweet-scented osmanthus cake. The man became addicted to it and came to eat it every day, completely unaware that his life was locked with this snake.
