Xian: the state of immortality that all cultivators strive to achieve. However, there is a dark energy that lies underneath—the forbidden Mo Dao, or demonic path. Through an unfortunate series of tragedies, this is the path that cultivator Wei Wuxian experiments with during his teachings. His rise in power is accompanied by chaos and destruction, but his reign of terror comes to an abrupt end when the cultivation clans overpower him and he is killed by his closest ally. Thirteen years later, Wei Wuxian is reincarnated in the body of a lunatic and reunited with Lan Wangji, a former classmate of his. This marks the beginning of a supernatural mystery that plagues the clans and threatens to disrupt their everyday life. Mo Dao Zu Shi follows these two men on their mission to unravel the mysteries of the spiritual world. Fighting demons, ghosts, and even other cultivators, the two end up forming a bond that neither of them had ever expected.

Continuing his masquerade as the deranged lunatic from the Lanling Jin Clan, Wei Wuxian resides in the Cloud Recesses while his former cultivation classmate, Lan Wangji, searches for answers about the demonic severed arm they have in custody. With an overwhelming dark energy emanating from the arm, the two are forced to work together in order to keep it contained. However, the demonic arm is not the only dark force lurking in the region, and as spiritual tensions rise in the mountains of the Gusu Lan Clan, it is up to the two of them to try and restore the natural order. The story of Wei Wuxian's fall from grace continues as more light is shed on his descent into the path of demonic cultivation. The demonic arm only further strains his mischievous spirit. This is the time for him to prove that he has truly broken free from the forbidden path and is not the maniacal sorcerer that everyone remembers him to be.

Along an empty road in the rural countryside, Wei Wuxian and Lan Wangji stumble across a stone plaque that reads "Yi City." Still on their quest to unravel the mystery behind the cursed severed arm, they venture into the deserted city to obtain further leads. However, with the appearance of a mysterious new cultivator, the demonic arm investigation leads Wei Wuxian and Lan Wangji to a plot that threatens the cultivation world as they know it. The gravity of the new situation escalates when the two find it involves the chief cultivator of the renowned Lanling Jin Sect—Jin Guangyao. As the pair continue to piece together the crucial conspiracies of the cultivation history, their friends and colleagues grow suspicious of their motives. With the world against him, Wei Wuxian must prove he is not the demonic sorcerer people believe him to be to regain their trust and save the cultivation world from the sinister evil lurking within it.

The Shi siblings have a lot on their plates, such as needing to stay frugal, passing their exams, and constantly dealing with each others' antics. Older brother Fen's frivolous demeanor often gets on his younger sister Miao's nerves, leading to physical but comedic altercations. Fortunately, their friends are always around to offer a helping hand. Kai Xin is Fen's well-meaning best friend who rivals Fen's absentmindedness but makes up for it with his athleticism. Miao, on the other hand, is often accompanied by her bubbly companion Miaomiao. The most recent addition to the group is Wan Sui, who is desperate to conceal his wealth but remains tirelessly loyal to his peers—sometimes roping his younger brother Xing into their excursions. Sometimes, the friends' roundabout means of problem-solving backfire. However, no predicament is going to prevent them from discovering how fun high school life can be.