When the earth is torn apart by a "gate", zombies are rampant, alien observers arrive, and mankind faces the end of the world. Structural engineer Cheng Kang struggles to survive in the ruins and meets An Jie, a boy who has been bitten three times without mutating, and An Yu, a sister who has lost her brother. They discovered that this disaster was a cosmic screening. And some people choose to become gatekeepers - paying an eternal price to exchange for the peace of human beings from generation to generation.
"The barrier is a door. On this side of the door are us, and on the other side of the door are the gatekeepers who protect us."
