Somewhere in the vast realm of the Internet, there is a message board called "Jigoku Tsushin (Hell Message)", which could only be accessed at the stroke of midnight. When grudges are posted on the website, Hell Girl will appear and drag the nemesis into inferno. Such rumor seems to be an urban legend that is believed among children but it is not just a rumor. Her name is Ai Emma. Usually, she is a quiet girl, but when she sympathizes with the grudge, she turns into Hell Girl. Although not mentioned in the rumor, it is necessary to reach an agreement with her. In order to send the target to Hell, the client's soul will be destined to go to Hell after the his/her death. Clients who get their revenge with the help from Hell Girl will have to live the rest of their lives with an engraved cross mark on their chests.