Plot synopsis: Ma Nan and Xiaoyu are a couple who have been in love for many years. Ma Nan bought a property in the suburbs, just in time for Xiaoyu's birthday. So he called his colleagues and friends and the party was held in a cheerful atmosphere. Next door to Ma Nan's house lived a couple who often quarreled. The unusually loud noise aroused the curiosity of party-goers. They went next door together to find out, but unexpectedly found a terrifying and bloody murder scene. The apartment, which was originally sparsely populated, seems to have turned into a huge haunted house. Flickering lights, shrill screams, and maddened murders. A plague-like virus spreads freely in the apartment.