Lin An, a patient with severe obsessive-compulsive disorder, is extremely paranoid about the number 99. When he was five years old, his mother promised to come back after counting to 99 but disappeared. He accidentally entered the abandoned hospital dungeon of a horror game, and others died tragically one after another due to fear. However, he suffered from obsessive-compulsive disorder and frantically struggled with numbers and regularity in the face of weirdness. Instead, he suppressed all kinds of weirdness and successfully passed the level. In the game, he encounters a mysterious baby mother, confronts the selfish veteran player Chu Yunze, and unexpectedly unlocks a warm and weird teammate. Finally, he reveals the truth about his mother's disappearance at the final level, and discovers that this terrifying game was originally set up by his mother to find him.
