Checking in to the Apocalypse: I Want to Subvert the Dark Age

This is a story about checking in to upgrade and trying to survive in the apocalypse. Gao Jun, who came from the new era, accidentally traveled to the post-catastrophic Earth, and was inexplicably bound to a check-in system. At that time, the earth was infested with zombies, cities were reduced to wastelands, and civilization that had accumulated for thousands of years collapsed. In order to survive, Gao Jun had to follow the system requirements and complete the check-in task with all his strength, while facing the test of life and death again and again...