Supernatural Event?

Inside the Xia Du Base.

"Do you think the aliens are aware we're building the Buried City?" Councilman Zhou asked with a hint of concern.

"I do not believe so!"

Colonel Chu shook his head. "Zhang Tao flew a spacecraft to the moon. We set particles on it and five minutes later, they indicated they were observed. This suggests the aliens have not made any advancements in quantum entanglement."

"The thirteen secret bases in the uninhabited lands have the same particles, yet they remain unobserved…"

These particles were set up very discreetly. Even the local troops were not aware of them. Initially, they were used to determine whether they were under surveillance by foreign forces. Now, they could be utilized to monitor alien activity.