Kevin Parsons is a student on the verge of great things. Then suddenly everything changes. Driving home, Kevin"s mobile rings and a demonic, threatening voice demands he confess his sins or his car will explode. Kevin"s world is turned into chaos when the demonic voice is identified as the insane serial killer, known as the Riddle Killer. As Kevin embarks on a frighteningly twisted race against time, he is contacted repeatedly by the Riddle Killer and told to confess his sins or die. What "sin" from Kevin"s past is motivating the killer?