Eighteen years ago... Xipingzhai is a small village in the mountains of Yunnan and Guizhou. Because it is surrounded by mountains, there has been no electricity for more than 40 years since the founding of the People's Republic of China. Only a rugged mountain road is connected to the outside world. Except for sending people to the county town every month to replace necessary medicines, this village with hundreds of people has no other contact with the outside world. Xipingzhai seems to live a self-sufficient paradise life. However, this extremely closed small village has rarely ushered in the footsteps of outsiders. It is a scientific expedition team that has come from afar. This scientific expedition team with more than ten people traveled through mountains and rivers and took two days to walk from the county town to the village.