Marty (Kristen Bell) and her boyfriend Josh have been a little estranged recently. After many unsuccessful phone calls, she visits Josh, but what she sees is the body of her boyfriend after he committed suicide... Marty is trapped in self-blame, and the illusion of her boyfriend lingers in front of her. Not long after, when Marty and her friends were using online chat software, Josh's instant message suddenly came. Marty suspected that someone was using her boyfriend's computer and asked a friend to check it, which led to her friend's terrifying experience at Josh's house... On the other hand, Marty tracked down the whereabouts of the computer and met Dexter, a young man who bought the computer. The latter found a series of strange videos in Josh's computer. In the video records, Josh said that he used hacking technology to release terrifying things, and he could no longer control it. In the suicides and abnormalities of the people around her, Marty increasingly realized that a cloud of terror spread through the Internet was quickly covering the entire city...