Did the world return to six months ago? This is a chance? Or repetition of despair? A catastrophe, a zombie virus that hit the Earth. Three years to survive a devastating and desperate life through dozens of death crises on a ruined planet. Eventually, I couldn't stand it anymore, and I was hit by a zombie horde.... when I opened my eyes again ... I was back in the past just six months before the zombie virus came into the world! In the next six months, this peaceful world will perish.