One day, a friend of Chun Yu (Gillian Chung), a senior girl in college, received a mysterious text message. She took Chun Yu to an abandoned teaching building and asked Chun Yu to take photos for her. When she looked at the photos on the computer, Chun Yu felt only fear and had an ominous premonition. Soon, Qing You died strangely, and Chun Yu saw a text message "GAME OVER" on her mobile phone. Later, Qiu Yu received a text message from the dead Qing You, "Do you know what the nineteenth level of hell is?", and was horrified again, but she couldn't help her curiosity to find out the truth about Qing You's death. She followed the prompt of the mobile phone text message to enter the hell world in the game, and her other two friends Wen Ya and Su Lan, who were also playing this game, suffered the misfortune of "GAME OVER" in different game stages. At the same time, detective Ye Xiao gradually locked the target person on Yan Mingliang (Patrick Tam), a professor of psychological counseling at the university, during the investigation.