After the disastrous launch of an experimental 7G cellular network warps reality itself, Japan is left devastated with civilization collapsing and being reduced to scattered, isolated settlements. In addition, the 7G Incident has created strange phenomena and affected the surviving population in various ways, such as transforming the residents of Agano into intelligent animals once they reach the age of 21. Two years after the 7G Incident, you comes across evidence that your missing friend and classmate Yoka Nakatomi is actually alive and well in Ikebukuro. With the warped landscape too dangerous to travel on foot, you and the rest of your friends commandeer an abandoned passenger train with the intent to follow the rail line to Ikebukuro and reunite with Yoka.