After his death, Shen Yuan found himself in the world of a Xianxia (supernatural martial arts) novel that he likened to trash shortly before he died. As per the genre, one would expect him to reincarnate as the protagonist, right?
Wrong. Instead, he transmigrated into the body of Shen Qingqiu, the titular "scum villain" who, in the novel's canon, eventually gets killed by the actual protagonist Luo Binghe for being a sadist teacher. Determined to avoid the same fate, Shen Yuan uses his knowledge of the novel's plot and tropes to endear himself to the characters (especially to the protagonist), to ensure that he keeps his life.
Unfortunately for him, he's accompanied by a video game-like "System" that monitors and grades his actions, keeping him from taking too many liberties with how his character acts and how the story progresses. And if he ignores its warnings, the consequences will be deadly. Thus his foray into the world of cultivation begins..