Lu Yan, a graduate student in the Department of Geology, accidentally broke into a mysterious sinkhole blocked by the military in order to track down clues about the mysterious disappearance of his mentor. During a landslide, he was "parasitized" by an obsidian crystal that was peeled off from the rock formation and beat like a heart. He has since gained the ability to listen to the "memory" of all things - [Abyss Echo].
This crystal is the legacy of a certain "Earth Fire Civilization" that has long since disappeared in prehistory. They are not ancient people, but "pioneers" who master geological energy and biotechnology. In order to avoid a catastrophic disaster from the universe, they moved the entire civilization into the center of the earth and used unimaginable technology to create an underground world that relied on geothermal heat and special ecological cycles.
The disappearance of the mentor is related to this underground world. In order to find his mentor and solve the mystery of his own mutation, Lu Yan formed a temporary expedition team: a retired female soldier with extraordinary skills and responsible for security; and a "theoretical" friend who was proficient in paleontology and mythology. They followed the broken "voice" provided by [Abyss Echo] and embarked on a path of no return to the center of the earth.
In this bizarre underground kingdom that subverts all scientific common sense, they will face not only deformed behemoths that are hungry for light, suspended temples full of ancient mechanisms, but also a mysterious organization that also covets the legacy of the "Earth Fire Civilization".
