Modern technology is developing rapidly, and various communication methods are becoming more and more advanced, which greatly shortens the distance between people and makes people's privacy nowhere to hide, and even life is greatly threatened. In a certain high school, death chain letters have been popular recently. The letters are sent to other people's computers and mobile phones via email. Once received, they should be forwarded immediately, otherwise their lives will be in danger. Computer game fan Nell Knaus (Cody Kasch) accidentally received a chain letter. He and his sister Rachel (Cherilyn Wilson) jokingly sent it to Johnny Jones (Matt Cohen), Jessie Campbell (Nikki Reed), Dante and other friends. Friends also regarded it as a joke, or deleted or forwarded it, and didn't take it to heart at all. However, terror actually came. That night, Johnny was brutally murdered. The evil and perverted chain killer is getting closer and closer...