After the death of her policeman father, Xiaomai begins to look over his old journals filled with notes about the cases he investigated over the years. The mention of a purple scarf in the notes particularly catches her attention, prompting her to purchase a similar scarf from a mysterious website that claims to sell everything, as long as one can pay the price. Soon after, Xiaomai's close friend is found dead, strangled by a purple scarf. All of this awakens Xiaomai's memories of her childhood sweetheart Qiushou, whose mother was also strangled to death with a purple scarf by an unknown killer. Xiaomai and Qiushou grew up together and fell in love, but he suddenly disappeared from her life 15 years ago without a word. She begins to believe that Qiushou has returned and may be seeking revenge.
Chun Yu is a university student whose life is thrown into unspeakable turmoil when she receives a chilling text message that reads: “I know what the 19th floor of hell is.” Soon, she realizes that other students on campus have received the very same message. Before long, she learns that she has been sucked into the macabre reality of a mobile game that takes place in a ghostly “haunted” building where every floor is full of dangers, horrors, and terrifying secrets. Worse still, she observes, when unwitting players fail to beat a level in the game, they immediately fall into a coma. With no other choice, she begins to play the game, where she meets fellow player Gao Xuan. The duo begins to navigate the perils of the building together, slowly heading toward the dreaded 19th floor. But what awaits them if they make it to the game’s final, decisive level?
