The year is 20XX. Winter has just begun.

Coming from who-knows-where, "that" arrives, marking the end of normal life. Falling in love for the first time, there are still those who don't know. There are those who have found a reason to stay alive and those who haven't; either way, everyone is torn apart equally. Still-warm bodies are rolling; the bodies which were once living turn into "those", breaking the world around them. The future of the world crumbles before people's eyes. Snow fell from the cloudy sky that day. For those young people, the time of barely clinging to life began.