The 404 Mystery

Four girls move into dorm 404 and soon face strange occurrences, including combing hair in the rain, white shadows in mirrors, and eerie peach-wood combs. After playing with the pen spirit, the incidents worsen until a classmate, Xiao Yu, dies mysteriously. The main group investigates the past of the red-clad senior sister, He Xiaocui, from ten years ago and discovers the dorm manager is hiding her spirit tablet. The introverted girl, Meng Meng, is actually the mastermind behind the scenes; as a child, her aunt Xiaocui was cruelly bullied and killed at school, and she has long been bullied by her roommates, so she sets traps to retaliate. Ultimately, Meng Meng is arrested by the police for the crime, while the other roommates involved in bullying receive disciplinary action, and the four girls complete their self-redemption through anti-bullying lectures.