Lu Chen, a senior student at Jiangcheng No. 3 Middle School, is a taciturn ordinary student with average grades during the day. At night, he is the descendant of a top killer hiding in the shadows of the city. He pursues profit first, is cold and suspicious, and only believes in the knife in his hand and the numbers in the card. Until the childhood sweetheart and genius doctor Gu Qingyi returned from the capital, she forcefully broke into the lone wolf world carefully constructed by Lu Chen with the secrets and goodwill that could shake the ancient family. When the roars of strange beasts began to echo outside the city walls, when the tentacles of the Guwu family reached out to civilians, and when the rules of the "inner world" hidden underground in the city gradually surfaced, Lu Chen discovered that his solitary survival philosophy was failing. He must choose between the cold killer code and the warm bond brought by Gu Qingyi. In the chaos of urban martial arts, he must fight his own way and become the urban Yama that makes all enemies tremble.
