A huge hole is located at the end of this alley.

Vanna came to the edge of the hole. The alley came to an abrupt end here. The ground and the ceiling disappeared in front of her as if they were swallowed by something invisible. On the opposite side of the neat fracture, the huge and empty darkness even made her, the judge, feel a huge pressure. The instinctive fear of human beings when facing such a huge dark space surged like a tidal wave.

Morris also came to the "entrance" of the hollow cave. He raised the lantern in his hand, but the light from the special underground lantern seemed to be swallowed up directly - the light did not disappear, but because the dark space in front was too huge, there was nothing to reflect the light in all directions. The light gradually faded in the darkness, and finally only illuminated a steep slope extending downward from the pit wall, while the rest of the place was still shrouded in darkness.

"This... no matter how you look at it, it can't be a structure that originally existed in the mine," Vanna took a deep breath and looked back at the mine tunnel that the group had walked along. "The normal passage ends here... This location should be the 'stone wall' mentioned in the report."

Morris bent down and carefully examined the small area of ​​the inner wall of the hole illuminated by the lantern. "It feels like there was some huge 'thing' filling this place, but now that thing has disappeared, leaving a big hole."

"How come such a large cavity didn't collapse but stabilized instead?" Duncan couldn't help but frowned. He looked up at the darkness above with a worried tone, "If a collapse occurs here, at least one-third of the upper city will be in big trouble."

At this point, he suddenly turned around and looked at Agatha: "Are you okay? You seem to be a little bit off from the beginning?"

"I... can't see the 'void' you mentioned clearly," Agatha said hesitantly, "I only see a huge and distorted reverberation here, and the wind is full of noise. Is there really nothing in front of it?"

"There's nothing, at least visually, and I can't sense any pollution left by supernatural powers," Vanna nodded affirmatively, and then thought for a moment, "But you can feel it... maybe it's because the things left here are resonating with you?"

"I don't know," Agatha shook her head, then turned to Duncan, "What do you think?"

"We should go in and take a look at the situation inside." Duncan had already made the decision. Then he waved his hand in the air, and a ball of dark green flame appeared out of thin air beside him. A skeleton bird wrapped in flames flapped its wings and flew out from the flames, landing on his shoulder with ease.

Ai tilted his head and looked around: "The old driver is coming! The old driver is coming!"

"We cannot rule out the risk of this 'cave' collapsing, so take this pigeon with you," Duncan explained. "Once you enter, do not disperse. Always keep an eye out for any signs of instability around you and pay attention to any movement above your head. If there are any signs of collapse, teleport everyone."

"Yes, Captain." "Understood." "Okay." "Hehe..."

Duncan tapped Alice on the head, then confirmed the terrain at the edge of the cave, took a deep breath, and was the first to step out into the darkness.

Others followed closely behind.

Stepping into the cave, there is a very steep slope, and the slope is not continuous. There are height differences and winding "forks" in the middle at any time. You have to be extra careful with every step you take, and this winding and difficult slope extends into the depths of darkness, as if it can reach the bottom of the cave.

The ramp gave the impression of a deep indentation in the rock left by some long-term erosion.

Duncan walked forward cautiously in the darkness, with the dark green flames burning and spreading quietly under his feet. The endless spiritual fire illuminated the small space around the path and left a striking "flame path" behind everyone. Looking back, one could see the flowing fire like lines, winding in the darkness to outline the road leading to the cave exit.

When exploring such a huge and dark underground space, it is very important to leave good road signs. Although there are pigeon spirits as the ultimate means of evacuation, out of caution, Duncan still left his own flames along the way - these flames also extended his perception, helping him to grasp the subtle changes in the inner wall of the cave at any time.

In Vanna's hand, a storm sword made of ice had condensed. She held the sword in one hand, alert to the monsters that might be lurking in the vast darkness. Alice carefully supported her head the whole time, fearing that she would slip and be separated from her head in the darkness. Agatha, because her perception was affected by some kind of "reverberation" in the cave, had to be supported by Vanna and took cautious steps on the rugged slope.

Morris was curiously observing the stones on the roadside under his feet all the way.

"Very dense rock... and it seems to be fused and squeezed together." He raised the lantern, his eyes flashing with a faint silver light, and observed as far as possible. "If the inner wall of this cave is composed entirely of this rock layer, it may explain why it can remain stable after its 'contents' disappear. These stones form a dense and thick 'inner shell' that supports the entire structure."

He hesitated for a moment, then said uncertainly, "But an inner shell alone may not be enough. For such a large cavity, there should be other supports in the middle."

Fanna couldn't help but turn her head and look at the old man: "How much do you know about this field?"

"Mathematics, history, chemistry, mysticism, physics, a little knowledge of geology and mining, and some knowledge of combat, firearms, machinery, and blasting," Morris said casually, "Any questions?"

Vanna was stunned: "How... did you do that?"

"Just read more books," Morris said. "It's not surprising that I know these things. After all, I am a historian."

Vanna looked at Morris with a strange look, wondering which of the many subjects he had just mentioned, except for firearms, combat and blasting, had anything to do with the professional requirements of a "historian", but she hesitated for a long time and didn't dare to say it out loud.

Agatha, who was supported by Vanna, had an even weirder expression on her face. The gatekeeper was once again deeply shocked by the followers around Captain Duncan. The last time she had a similar feeling was when she knew Vanna was a "sports student"...

However, Morris himself was obviously not aware of this and caused everyone to marvel. His attention was now attracted by the "stone" under his feet again.

Under the light of the lantern and the green fire, the surface of these stones has a slight metallic luster, and I don’t know if it’s an illusion... there seem to be some special patterns on their surface.

The old scholar bent down, picked up a piece of gravel and examined it curiously.

He suddenly stopped.

Duncan also stopped and looked at the stone in Morris's hand curiously: "Any questions?"

After several seconds, Morris seemed to suddenly react and spoke slowly with a strange tone: "...It's boiling gold."

Agatha turned her head immediately: "Boiling gold?"

"Boiling gold ore, the purity is almost enough to be directly stuffed into the steam core reactor..." Morris muttered to himself in astonishment, and then quickly bent down to pick up another piece of gravel. After checking it, he simply squatted down and carefully examined every rock under his feet. The more he checked, the more frightened he became. "This is also... No wonder, no wonder I felt that the texture of these 'stones' was very strange just now, but I couldn't find it because it was too dim..."

The old scholar suddenly stopped and looked up at Duncan and Agatha.

The expression on his face was strangely surprised, but also vaguely filled with the excitement of having made a great discovery: "It is indeed boiling gold, Captain, Agatha - this entire cave is made entirely of boiling gold! At least the bottom of the pit is covered with raw ore!"

Everyone fell silent, and in this silence, Duncan could clearly feel Agatha's emotions fluctuating violently, and Vanna could even feel that her body was trembling slightly.

No one understands the meaning of "boiling gold" better than a native Frostman.

"This is all boiling gold. We saw some remaining boiling gold veins in the mine tunnel before," Vanna said softly, holding Agatha's hand. "It looks like Frost doesn't have to worry too much for at least a while."

"Yes... don't worry... there is boiling gold here..." Agatha murmured to herself, but her tone was strangely complicated, "But why, why are there these things..."

"Will the erosion of the Deep Lord leave behind boiling gold?" Duncan couldn't help but frown. "If the intelligence is correct, this big hole should have come from this..."

Everyone seemed to suddenly become serious, so much so that even Alice, who was usually slow to react, could sense the change in the atmosphere. Miss Doll couldn't help but come over and gently pull Duncan's arm, and said carefully: "Captain... What is boiling gold?"

Duncan: “…”

With everyone being so serious, it's hard to believe that this fool can still be such an unwavering fool.

He sighed: "Boiling gold is the foundation of modern industry and the energy source for all steam-powered machinery - just like people need to eat, machines also need boiling gold to operate."

Alice listened with a half-understanding, and after a long while she nodded in sudden realization: "Oh——"

Duncan didn't care whether the illiterate puppet really understood or not, his gaze once again turned to the darkness ahead.

This huge underground cavity has completely aroused his curiosity.

If this entire cave is made of extremely pure boiling gold... then what will be waiting for him in the deepest part of this cave?