Jack Harmon finds a cell phone on the school bus. He raises the phone to his ear and hears a girl's voice: "Hi, Jack. Don't scream. I've been waiting for you. I'm your new friend." Jack thinks it's a joke. He tries to end the call, then turn the phone off, but the girl's voice won't go away: "Don't make me angry, Jack. I'm warning you." Jack is puzzled and a little frightened. He must obey her every wish.