A high school girl becomes involved in a murder mystery that revolves around a dating simulation game that has currently become popular on mobile phones. A woman who seemingly exists only as a character within the game is somehow killing all the male players one by one.

A group of seven random players are chosen to participate in the next 'Twilight Syndrome' game created by Makino Shuzo. This time, it is at an amusement park, known as the Twilight Zone.