After Furbollo made his bold declaration of "getting to the bottom of this truth"...

The next thing they did was prepare for sleep. 

After all, it was already late into the night, and both of them could barely keep their eyes open.

Though dawn wasn't far off, even two hours of sleep would provide some rest.

Lin Yu lay on the bed while Furbollo very considerately took out a sleeping bag. He replaced his dog-fur earflap hat with a wool nightcap before crawling inside.

"Tomorrow I'll definitely investigate this dungeon from top to bottom until everything's crystal clear! Then we'll both get the 'Threading the Needle' reward together!" Furbollo declared optimistically.

"Threading the Needle" was an achievement that, like "Master of Control," provided extra rewards on the [Settlement Interface]. 

Typically earned by uncovering hidden "truths" in non-puzzle type dungeons.

Listening to Furbollo's words, Lin Yu responded:

"Then I'll leave it to you."

Having this so-called 'Detective' around did save him considerable trouble.

Though he wasn't particularly concerned about the "Threading the Needle" reward, he certainly wouldn't refuse it if offered.

Moreover...

His second Promotion task would most likely be completed in the process!

Of course, this didn't mean Lin Yu planned to completely hand over the reins.

He'd begun trusting this 'Detective' slightly more, but he still needed to keep puzzling through the dungeon's various mysteries himself.

Which was precisely why Lin Yu chose to sleep now.

Based on previous dreams... Lin Yu suspected sleep might be another means of gathering information.

Soon, Lin Yu drifted into slumber.

And sure enough...

When Lin Yu opened his eyes again, he found himself amidst howling winds and snow.

In the vast blizzard, a young man with long curly hair—wearing professional equipment and carrying a backpack—was digging into the frozen ground with a shovel.

Circling to face him, Lin Yu recognized the curly-haired youth's appearance.

It matched the researcher on the ID card he'd seen earlier: "Vale Valetti."

Soon, the young researcher unearthed several corpses from the frozen earth.

His expression turned grim as he knelt, using gloved hands to clear away more frozen soil before retrieving a device resembling an ammeter from his backpack.

"Zero soul readings again... Damn it! It's really true!"

As if realizing something, Vale took out a transparent case from his backpack.

The container held some squirming, semi-liquid black paste. Vale pointed the case at the corpses and took another reading with his device.

"Beep beep beep!"

The instrument emitted sharp alarms.

Vale seemed to completely break down, sitting in the snow with his face in his hands.

"So it really was our fault—the 'leak' caused these deaths!" Vale Valetti muttered painfully, tugging at his own hair.

Lin Yu quietly observed the young man's anguish while calmly analyzing:

"So... combining this with the notes from earlier, these deaths weren't caused by 'natural disasters,' and the monsters here aren't native to this place..."

"Rather, they resulted from something leaking from some 'organization.'"

"The Black Oil seems connected to these deaths too."

As Lin Yu pondered, Vale Valetti on the ground seemed to reach some resolution. He stood up and trudged into the snowstorm.

Lin Yu quickly followed.

Vale soon arrived before a cave entrance—not natural, but sealed by a metal door.

Producing a metal key, Vale unlocked the door and entered.

Lin Yu tried following, but an invisible force repelled him at the threshold.

Then...

A voice spoke behind Lin Yu.

"If you're seeing this, you've found what I left in the cabin."

The gentle voice belonged to a faint, translucent figure of the curly-haired young man standing behind him.

His identity needed no explanation.

"You're Vale Valetti?" Lin Yu asked, turning toward him.

The figure nodded in confirmation.

"Yes, I'm Vale Valetti, B-3 clearance researcher."

"Though... more accurately, I'm a consciousness fragment Vale Valetti left behind."

Lin Yu nodded. "I read your notes... What were you trying to accomplish?"

"What really happened inside Extreme Winter Mountain?"

"What is 『Chate』? What's this 'leak' about? How does Black Oil connect to those deaths?"

"And who built all these outposts in the mountain?"

Vale shook his head at Lin Yu's rapid-fire questions.

"Sorry, I can't answer those directly."

"My current existence is intrinsically linked to 'that thing.' If I answer here, my 'answers' and 'thoughts' will be detected."

"Then... you'd lose any chance of ending this."

"You might not even escape alive."

Vale's answer didn't surprise Lin Yu.

If solutions could be handed out in dreams, Vale wouldn't have made everything so convoluted initially.

"So you can only give me various 'hints'?"

"And only after I've discovered certain things first?"

Lin Yu asked.

"Yes, hints," Vale murmured. "With your intellect, I believe you'll deduce what must be done."

"I'm starting to understand," Lin Yu said, eyeing the metal door. "Find this cave, open that door."

"Using the key left with your ID and notebook."

As Lin Yu spoke, hope glimmered in Vale's eyes.

"Yes, yes—I can't reveal more."

"But... whether you seek truth or survival, trust me, this is your best path!"

"You're clever enough to end this."

Lin Yu sighed. "Understood... Though I should correct you—I'm not the smartest one here this time."

"There's a far more professional 'Detective' with me."

Vale stubbornly shook his head. "No, no... You're absolutely the cleverest."

"After all, your wisdom has earned divine recognition."

Pointing at Lin Yu's wrist, Vale continued:

"Even the God of Change who governs truth and void left his mark approving you..."

"So I believe in you too!"