The "space-time tremor" a hundred years ago was not an accident, but the product of a failed man-made experiment. The "memory fragments" of the experiment leader were the key to uncovering everything, but they were hidden in the deepest part of the "rift domain" by the crackkeepers.
Some rift explorers discovered that their relatives did not die in the "rift" incident, but became rift keepers or even participants in the experiment that year.
The top level of the Order Maintenance Bureau has long been lightly "contaminated". Their real purpose of covering up the secret is to use the power of the "rift domain" to achieve some kind of domination ambition.
