She turned around and looked toward the back wall of the cave.

“Let’s look over here, there’s a crack up there.”

Su Tang shone the light on the cave wall and discovered an inconspicuous crack on the back wall.

The two walked to the crack.

The crack was narrow, but a faint, warm breeze carrying a sulfurous smell did seep out, along with a tiny glimmer of light.

Qin Ye took out his military knife and slashed it hard against the cracked rock wall, leaving only a white mark. The rock was not as hard as the one at the cave entrance.

"Looks like there's a chance."

"How about... we go in from here and take a look?"

"Wait a moment."

Before Qin Ye could speak, Su Tang grabbed him.

"Just in case, wear this."

With a wave of her hand, two lightweight silver-gray protective suits and matching transparent face shields appeared on the ground.

"There may be toxic gas or oxygen deficiency inside."

Qin Ye looked at the futuristic outfit and his lips twitched.

He, a tough soldier, now looks like someone going on an alien expedition.

However, he didn't ask any more questions and obediently dressed himself.

Su Tang quickly changed as well. The two looked at each other and saw their own reflections in each other's transparent masks, and couldn't help but laugh.

"I'll clear the way."

Qin Ye regained his soldierly vigilance and composure. He shielded Su Tang behind him and used an entrenching tool to widen the crack into a hole large enough for one person to pass through.

A warm breeze carrying the smell of sulfur immediately blew out.

Qin Ye took the lead, followed closely by Su Tang, and the two of them crawled into the newly opened cave.

Behind the cave entrance is a narrow but very dry natural rock passage that slopes downwards.

On the rock walls of the passage, some moss with a faint fluorescent glow clung to the dark passage, providing a hazy light.

The further you go in, the higher the temperature becomes, and the stronger the smell of sulfur gets.

Su Tang made a judgment in her mind: this was likely a natural passage leading to a geothermal activity area.

She couldn't help but marvel at the wonders of nature.

The passage wasn't long; after walking for about half an hour, the view suddenly opened up ahead.

A wave of heat mixed with thick moisture hit them, and the sight before them made them both stop in their tracks.

A huge, domed underground cavern appeared before them.

In the center of the cave is a sizable lake, with steam rising from its surface, clearly a natural hot spring lake.

Some peculiar, luminous plants and fungi also grow along the lake.

The entire cave was warm as spring, a stark contrast to the icy world outside.

Qin Ye took off his mask, took a deep breath of the warm, humid air, and was so shocked that he couldn't speak.

"This...this is..."

He had lived for nearly thirty years, traveled all over the country, and seen all kinds of dangers, but what he was seeing before him was completely beyond his comprehension.

He muttered to himself, "Good heavens..."

Su Tang was amused by his appearance.

She also took off her mask and used instruments to test the air and water quality.

"The air is fine, and the water is mineral-rich hot spring water, which is good for your health."

She pointed to the fleeting shadow in the lake, her eyes sparkling.

"And it looks like there are fish in there."

Qin Ye's attention was immediately drawn to it. He went to the lakeside and saw several transparent fish with strange appearances swimming leisurely by.

"There really are fish!"