In Glass County, several teenagers from high-school are slaughtered and their severed bodies are found in the working place of their fathers. The retired detective Mike (Antonio Mastrantonio), who is the absent grandfather that is trying to approach to his granddaughter Nikki Reynolds (Joli Julianna), teams up with the inexperienced Detective Billie Vega (Kim Taggart) to help her in her investigation, where the slow janitor Troy (Sal Sirchia) is the prime suspect.<br /><br />The lame "Knock Knock" is a terrible movie: the story and the screenplay are ridiculously bad; the unconvincing acting is awful; the camera work is dreadful. The only thing that works is the cover of the DVD that induced me to buy it. My vote is three.<br /><br />Title (Brazil): Not Available