The Lee family lives in a multi-storey building. One day, Lee's mother falls down the stairs and dies. On the night when her spirit is believed to return, Lee's only son cannot be found. Mr. Lee gets the security team to help. Meanwhile, the ghost of Lee's mother appears. Mrs. Lee is scared off, and a mysterious person called Leon promptly turns up, so Mrs. Lee is saved. Leon is an expert ghostbuster. One of the residents, Kwan, witnesses how Leon fights with the ghost, and she falls in love with him although she knows that he has been mentally ill. Soon after that, Lee's mother appears again, and she tells the security leader, Mr. Lo, that her son and daughter-in-law in fact murdered her. The facts are revealed and the Lee couple force Mr. Lo to jump from the building. Meanwhile, Leon turns up again and shoots at Mr. Lee, making him fall from the building.