Grandpa, You're Rebellious in the Underworld

College student Zhang Di's grandfather rebels in the underworld, frequently appearing in his dreams demanding military pay. When Zhang Di accidentally activates a system while burning paper money, he meets two female demon wives sent by his grandfather and gets involved in a conflict between the human and demon realms. As he hunts monsters and upgrades in school and urban settings, he joins the Paranormal Investigation Bureau but is hunted by a mastermind behind the scenes. While uncovering the mystery of his past, Zhang Di begins his extraordinary life of hunting demons against the odds.