+++"Bang——"++++The roar in his head continued. Xiao Li turned over and sat up from the bed, reaching out to hold his eyebrows. The faint smell of gunpowder smoke seemed to be still around. He was confused for a moment and shook his head. ++++ "Where am I?" ++++ Xiao Li looked at the familiar furnishings in the familiar room, recalling the last memory before waking up: He was on the roof looking at the mess, the ruined world, and the groups of disgusting zombies. He happily picked up the gun in his hand and used the last bullet left for him. ++++ "Oh, I'm dead, no..." ++++ He shook his head, and the memory in his mind seemed to be divided into two parts. One was the memory of the nineteen-year-old that matched the current time and place, and the other was the memory of the terrible twenty-nine-year-old when all the unfavorable things and sins were revealed, and all the good things were gone. After comparing the same parts of the two memories before the age of nineteen, the twenty-nine-year-old Xiao Li successfully merged with his nineteen-year-old body. Reaching out to pick up the mobile phone beside the bed, Xiao Li raised the corners of her lips as she looked at "June 3, 2012" displayed on the screen. ++++ "Looks like I'm back." He turned on his phone and looked at the smile on the screen, almost bursting into tears. "Promise" He lifted his lips and uttered these two words softly, "This time, I will never let you leave first."