"What is this...?" Xu Xin picked up the bottle of grey potion.
[Special Treehouse Root Potion (Purple): Pour it under the treehouse to promote the development of its roots. Each potion can expand the treehouse's protection range by three kilometers.]
A purple-grade potion! And it's a potion that expands the treehouse's protection range!
Xu Xin's current treehouse protection range is three kilometers in radius. After using this potion, it will expand to a radius of six kilometers! This is not just a doubling; the radius doubles, and the protected area actually expands fourfold!
This means that after using this potion on his treehouse, Xu Xin's exploration range will become four times what it is now! Within this expanded range, there might be another resource area.
Good stuff, really good stuff. It's truly worthy of a golden treasure chest.
Xu Xin picked up the thin card again.
[Automatic Unlock Contract for Metal Products (Purple): Unlock all recipes for metal products. After using this contract, for all metal-related recipes, you only need to acquire all kinds of raw materials to automatically unlock them.]
Following the treehouse transformation contract, he obtained yet another contract, pertaining to metal product recipes!
With this contract, Xu Xin will finally no longer be limited to just making stone tools!
[Congratulations, you have opened the gold, silver, and copper chests, becoming the first survivor to find and open all three chests in this batch. The rewards will be distributed after the current jungle exploration activity ends.]
[Survivor, please keep it up, strengthen yourself, and strive to survive in this world.]
The mysterious voice sounded again.
He is the first person to obtain all the chests.
The activity isn't over yet, and he wonders whether others will find the golden chest.
To be honest, if it weren't for Keke's insistence to pull him down below where the golden chest was, he would never, given his cautious nature, have dug out the underground passage.
The conditions for obtaining this golden chest are truly too harsh.
Xu Xin shook his head, choosing not to dwell on these thoughts as he looked at the contract in his hand and decided to use it.
As before, the card representing the contract shattered and merged into Xu Xin's body, and he felt a surge of power pouring into every corner of his being.
This time, he felt not only stronger but also clearer-headed, quickly reviewing everything he had just experienced in his mind.
First of all, that gigantic Cannibal Flower must be the monster guarding the entrance to this underground world.
Underneath, this abrupt iron room has been buried for many years, just like the people in it, but those incredibly foul red mists in the room came from who knows where.
The people in the room weren't from this world, yet they brought tools and food from their original world here, suggesting their entry into this world differs from Xu Xin and these survivors, though he cannot figure out exactly how.
This task's golden chest and the secret of the underground space are bound together. Whoever finds the golden chest must have seen the secret of this underground world beforehand.
Those who cannot find the location of the golden chest naturally cannot discover this secret.
Who exactly is that mysterious voice? Why did it bring them to this world? Perhaps, was it to let them grow and then fight those monsters deep underground?
How were those monsters even created? The size disparity with the surface creatures is too vast.
He recalled the Lake Giant Python and the creek bottom giant crocodile; these two enormous, beyond-reason creatures must be from the subterranean realm, and very likely, the lake beneath connects to a kilometer-deep underground.
And then there's this potion from the golden chest.
Xu Xin examined the bottle of grey potion in his hand, which held about three hundred milliliters, weighing approximately the same as a canned drink.
The potion's function is to promote the development of treehouse roots, expanding its protection range. Could this imply that what protects Xu Xin and the other survivors from subterranean creatures is the treehouse's roots?
An image formed in Xu Xin's mind.
During the two hours of treehouse growth, as the treehouse grew above ground, its roots were simultaneously diverging below, extending outward for three kilometers.
The treehouse roots intricately spread underground, blocking monsters that try to emerge. Any appearing monster would quickly be transformed into dry, brittle specimens as the roots absorbed them.
So as the treehouse roots grow longer, the protection range also enlarges correspondingly.
Xu Xin felt this explanation seemed reasonable.
It explains why the mysterious voice could emphatically stress repeatedly not to abandon the small treehouse, as it is the most potent weapon against subterranean monsters and their greatest safeguard.
Having figured this out, Xu Xin's mood lightened slightly. According to what the mysterious voice previously said, the monsters underground will not attack them anytime soon, so they only need to focus on dealing with beasts on the surface.
The treehouse will protect them well.
Xu Xin placed the golden chest into his backpack. Though forged of gold and quite heavy, Xu Xin's strength has been boosted several times, rendering him no longer as he was before. Combined with a backpack that reduces weight to 20%, carrying the chest on his back poses no issue.
He actually looked forward to seeing what happens after collecting all three chests and completing the symbol.
Before leaving, he decided to take one last look at the underground world, as he likely wouldn't return for a long time after leaving this time.
Keke didn't walk to the edge of the cliff like him but stayed back, lying down, seemingly afraid, staying away from the cliff.
It remained a chaotic scene of wild monsters.
Giant monsters draped in seaweed, enormous Cannibal Flowers several times larger than those on the surface, blood-red vines everywhere, firefly-like creatures the size of small carts, and other colossal plants and animals impossible to find on land.
These are what he will face in the future.
He must rapidly enhance himself, acquiring the ability to confront these threats!
Xu Xin looked forward, his gaze suddenly fixed.
He saw numerous protrusions at the top of the entire underground world.
Xu Xin's current position was akin to a light on the ceiling of a room, and those protrusions were other lights.
"These protrusions must be the other survivors' treehouses, or rather, their roots," Xu Xin mused.
According to his speculation, the inside of these protrusions should be a complicated network of treehouse roots, protecting him and the other survivors from the interference of subterranean creatures.
"Though we don't know who brought us here, they should definitely be playing a big game."
Xu Xin took one last glance at the underground world and then turned back into the iron room.
The skeleton still scattered across the ground. Xu Xin grabbed hold of Keke, who desired to play ball, and placed him upon his shoulder.
"Ying!" Keke protested slightly but obediently lay on his shoulder.
The upcoming task seems simple yet difficult.
Looking at the deep passage, Xu Xin felt his legs trembling.
Previously, just climbing down left his arms aching unbearably—now to climb up!
And he's even carrying a golden chest!
Xu Xin glances at the little creature on his shoulder, "Can you climb by yourself?"
"Ying ying ying!" Keke shook his head vigorously.
"Ying!" Keke wished to argue back, but each step of the stairs matched the length of his body; how could he climb!
With a sigh, Xu Xin decided to eat something before climbing up. Earlier, everything he ate last night had been vomited out, and though the contract swiftly restored his physical strength, he had been down here for such a long time that surely daylight had returned above, and it was definitely mealtime.
Just as he pulled out an apple to take a bite, a hissing sound of gas escaping suddenly arose beside him.
"What sound is that?"
Xu Xin turned around cautiously.
In his horrified gaze, the partly opened iron door automatically shut with a loud bang, followed by familiar red gas gushing from the gaps in the iron room's walls and floor, gradually spreading outward.