Escaped Immortals

"If you're thinking that someone had opened the Nine Heavens Eternal Grotto, then you're right, unfortunately." Senior Bai sighed.

"Shouldn't there be someone to guard that place? It would be disastrous if the criminals inside escaped, or am I wrong?" Yuan asked.

"No, you're right. However, there are people guarding the grotto. In fact, there are at least a dozen Immortals guarding that place around the clock, and there hasn't been a single moment when the grotto isn't guarded since the Primordial Era."

"Then how did someone open the grotto?"

"Simple. Someone managed to kill the guards and open the grotto."

"So all of the criminals inside are free now?" Yuan then asked.

"No, not all, which is the most fortunate part in all of this. Although the perpetrator managed to open the grotto, it was only for a brief moment, as the guards were able to call for backup before they died."