Chapter 300 – Exploring the Underground River

The invisibility magic circles were the true essence of Waterfall Cottage.

Apart from the front door and chimney opening, whose invisibility magic circle array stones were abbreviated versions with only a one-year lifespan, the array stones placed in the windowsill grooves of the four windows were all complete versions of the invisibility magic circle, fitted with charging and energy storage rune combinations that could be reused.

The slightly better quality low-grade magic ore had all been used on these four invisibility magic circles.

When she moved out, she could take the array stones with her. Later, in the wilderness, she could set up magic circles to visually conceal her camp at any time.

Finally, there was one fist-sized piece of Intermediate magic copper ore.

After Mo Lan used the Purification spell to remove impurities from the ore, she carefully used the Metal Shaping spell to melt it into a copper plate one centimeter thick.

Then she carefully inscribed a small-range Intermediate composite magic circle with warning and defensive functions onto it.

This one was not meant for use on a dwelling.

Magic ore of such fine quality—Mo Lan had been mining for so long and only obtained this single piece. Using it on a valley she could only live in for one year would be far too wasteful.

This magic circle was also portable. When activated during overnight stays in the wilderness, forget about ordinary wild beasts—even low-grade magical beasts couldn’t break through it, and it could hold off Intermediate magical beasts for a while too.

With it, plus a tent card, she could travel and stay anywhere throughout the entire Inner Region, never again having to worry about surprise beast attacks.

It would also prove useful during the fifth-year trials.

One could say this piece of magic copper ore was her greatest harvest from the entire mining process.

“Finally done!”

Mo Lan set down the magic copper plate at the study’s workbench and looked toward the magic ore crate beside her.

The previously full-to-the-brim magic ore crate was now mostly empty, with only the twelve magic gemstones remaining in the wooden box on her desk.

These were the ones she planned to use as energy cores for her magic robe, but since she still didn’t have suitable magic fabric, she hadn’t touched them yet.

The ordinary ore crate on the other side still held quite a few stones, and there were even more in the cellar.

But those had no use for now.

Half a month had passed while she was crafting the various magic items.

With eighteen days remaining, this school year was about to end.

Mo Lan had finally completed all the preparatory work related to her dwelling.

For the remaining eighteen days, she didn’t plan to sit idle.

After tending to the various crops planted in the valley and harvesting what was ready, Mo Lan took out the leftover black-haired wild boar hides from before and sewed herself a new large double-shouldered mining pack.

“Headmistress! If I’m not back by the fifteenth, please remind me!”

After informing the Guardian Headmistress, she entered the mine through the secret door in the cellar.

Such precious time was perfect for mining.

This time she wouldn’t bother with ordinary ore—she would only mine magic ore.

When the time came, she could craft it into magic items and bring them into the outer region survival trials.

When she grew tired of mining, she would read. The area near the underground river was spacious, and most Magic could be practiced along the riverbanks.

Mining and studying Magic—two birds with one stone.

But she still hadn’t reached the end of the underground river!

To find out exactly where this underground river flowed and whether there was a chance to use it to enter the core region directly, she didn’t dive straight into the caverns on either side of the river to search for ore this time. Instead, she flew directly downstream along the river channel.

Every so often she flew a stretch, then checked the map to see how far she was from the core region.

Only when the Metal Detection spell extended into the rock walls on either side of the river channel and detected traces of magic ore would she stop to mine for a while.

Mo Lan had noticed during her previous mining trips that although the underground river wasn’t perfectly straight—with plenty of twists and turns—its overall direction still flowed northward, toward the core region.

So the possibility that this river led into the core region was quite high.

Mo Lan followed the current downstream, and sure enough, her guess proved correct—the underground river really did flow into the core region.

She actually saw the Hedge Wall even underground.

No—it should be called a root wall instead.

She hadn’t expected the boundary line between the core region and the Inner Region to extend so deep underground.

But just like on the surface, when Mo Lan approached, it automatically opened a passage for her, letting her through.

As she flew further ahead, the river channel grew narrower and narrower. The portion above water shrank while the submerged portion grew larger and larger, until the water finally merged entirely into the stone wall, leaving no space for her to fly on a broomstick.

At this point, Mo Lan opened her map and discovered that her current position was beneath Moon Lake, on the northern side of Academy Mountain.

She thought for a moment, then stowed her broomstick in her spatially-expanded saddlebag and cast a Water Shield spell on herself.

This involved a special application technique of the Water Shield spell.

It had been discovered during the Age of Divine Descent by a Blue Witch who had taken an unconventional path and sought refuge on the ocean floor.

By spreading the defensive power of water elemental force evenly into a sphere that wrapped around oneself from all directions, treating the water itself as the object to defend against while not excluding air, one could enter the water with this shield and walk and breathe underwater.

When the Water Shield’s energy ran low, one simply needed to replenish it with Mana.

If one’s Water Shield spell proficiency wasn’t high enough to sustain a bubble large enough to cover the entire body, a compromise was to wrap only the head.

If even that wasn’t possible, one could make further sacrifices in defensive power, channeling all defensive force into displacing water while reducing protection in all other areas to the minimum. This would at least make the Water Shield bubble larger in area and broader in coverage.

The rain-repelling rune combination had actually been inspired by this application of the Water Shield spell.

It had also given rise to a whole series of water-related rune combinations: waterproofing rune combinations, moisture-retention rune combinations, water-repelling rune combinations, and so on.

However, the water-repelling rune combination used to create water-repelling gemstones—which provided underwater breathing and facilitated underwater movement—was an Intermediate rune combination. Although Mo Lan had practiced making one before, it required an Intermediate water elemental gemstone as the primary material.

She didn’t have that kind of magic gemstone.

Fortunately, the Water Shield spell served as an affordable alternative to the water-repelling gemstone.

The only drawback was that the Water Shield spell was an instant defensive Magic that required fairly high concentration to maintain. At most, she could spare enough attention to move her limbs—and not even very quickly at that—so casting any other Magic was completely out of the question.

Moreover, since part of the Water Shield’s defensive power was being used to repel water, its ability to defend against other forms of damage was reduced. If she encountered other dangers in this state, it would be very difficult to cope.

If she were in the wilderness, Mo Lan wouldn’t necessarily dare to use it. Having her Water Shield broken underwater would leave her far too vulnerable.

But right now she was within the core region.

Even underground, it was still the core region—there were no creatures that could threaten a young witch.

So Mo Lan didn’t need to worry about any powerful underwater beasts lurking in the water.

She was going to submerge herself and see whether the underground river connected to Crescent Moon Lake.