Throughout the entire stronghold, aside from a few Sentries on the Wooden Stockade walls, there were no more Sentries once one entered the fortress. As for patrols, they were practically nonexistent under Chen Mo's Spiritual Sense, and he could avoid them perfectly.
The main reason was that there was basically no formal military training here; everything was rather casual. Even the guards and patrols at the Black Fire base were already among the most numerous and strict in No Man's Land.
Thus, with the sweep of his Spiritual Sense, he could go wherever he wanted in the dark night. Being discovered would be genuinely difficult.
After approaching the cave, however, he had no way to enter and could only wait for a suitable moment. The cave entrance had Sentries unlike those at the fortress gate—two of them, holding firearms that were ready to fire at any time. One could tell at a glance that these Sentries were highly responsible. Chen Mo's Spiritual Sense even detected cameras just inside the entrance.
This greatly reduced the chance of entering without causing any disturbance. So he leaned against a corner and quietly used his Spiritual Sense to observe the interior of the hill.
As his Spiritual Sense spread inside, Chen Mo's heart sank at once!
Sure enough, although the entire hill was neither especially tall nor large, he had not expected the whole mountain to have been hollowed out, including the underground portion.
The underground area alone was more than a hundred meters long and wide, divided into several levels. Every level had layers of guards, along with all kinds of surveillance equipment.
Though this small hill consisted of rock and earth, after it was hollowed out, it had been reinforced with concrete. Taking the ground as the boundary, there were two levels