Ai, who attends a girls' school in Tokyo, spends her student life with her classmates from middle school, Fuyumi, Chiharu, Akiko and Yoko. One day, a chain mail called "murder net" arrives on Ai's mobile phone. According to rumors, "You can kill someone by including the name of the person you want to kill and sending it to them." Ai didn't believe the rumors at all, but Fuyumi tells Ai to put her name on and send it, and Ai reluctantly sends her the name of Fuyumi. Immediately after that, Fuyumi...