Wu turned and looked at Lera as his eyes shot open. Then, he quickly turned around to try to find a hiding place when Lera rose up and pointed back along the path where they came from.

“Did you already-”

“Yes.”

“How long do we have?”

“Enough.”

And so the two moved as quickly and quietly as they could back where they had just come from. There were still no sounds of footsteps from the unwanted visitors coming from behind, but that does not mean they can just slack off.

Along the path where they came in was a small branching-off point with one of the dead ends of 2 meters where they could hide, and Wu immediately activated a void domain shield layer before Lera set up her Sweeping Darkness cast to fully hide their presence. Then, while staying within the barrier they created, Lera projected cast Array in the air between them through a tiny gap in the shields.

Eventually, the vibrations from the footsteps started to show up on the edge of the projection before they slowly migrated towards the center of the non-dead end passage parallel to where they are and continued right up to the ledge where Wu and Lera were.

Wu and Lera watched the moving patterns nervously before finally letting their long-held breath out. However, before they could venture out of their hiding place, the pattern shifted once again, and a single pair of footprints circled back where they were.

Wu remained in the shadows with his fist clenched and the Casts at the ready when the footprint hovered the areas in front of them before moving on once again. As that individual moved further and further away, Wu also lowered his hands accordingly.

“Five people.” Lera said, “That matched the same number that the alarm showed me.”

Wu nodded before finally sighing, “I suppose we only have one conclusion…We know they are doing something funny with the underground river…”

“Yep.”

“and there’s no other reason people are in the mines at night…”

“Yep.”

Wu looked towards Lera, who was smiling back at him, and he hugged her lightly before dispelling the Void Domain shield layer, “Let’s go.”

Compared to the silent operations before, as Wu and Lera approached the ledge once again, the workers at the ground level were conversing just beyond the audible level from all the way up here, though, with the help of a simple amplification Cast from Lera, they were able to listen in like true stalkers.

The workers down below were utterly unaware of their presence, and the group of now a dozen people moved around the mines with robotic efficiency as they unloaded items and moved some of the actual mining tools out of the way. The five new people coming in later wore white, while the original seven wore the usual grey robes more reminiscent of what the townspeople donned earlier in the day.

“You have no idea how finicky these things are!” One worker in grey complained, “The moment it got anywhere near the water, the lines started glowing and shit!”

“And that’s why we have come to ensure you perform the work correctly and as instructed.” One in white replied calmly, “Show me what you have been doing.”

“You don’t believe us?” The first worker threw his arms up in protest when the ones in white ignored his plea and instead gathered around one of the spherical balls covered in a layer of cast materials. He mumbled something in the local dialect before squatting down to pick up one of the cast-laden spheres with the help of another worker before they combined to load it onto a cart pushed by a third worker.

“Shit…they are gonna move that thing somewhere else.” Lera said, “We need to see what they are doing next…”

“Launch it.” Wu said, sliding down his visor and zooming in to see the Wave signature of the spheres, “Launch your Scouting Eye down to the surface as soon as they depart to do whatever they wanted with the current ball thingy.”

“Are you crazy?”

“The spheres themselves are constantly emitting the Wave.” Wu said, handing his goggles over to Lera before she put it on. From this point of view, the glowing spheres had small tendrils of Wave lines extending out from it in all directions, “So if you attach your scouting eye to the spheres, then its presence would be hidden from those people down there, so long as you kept the Cast to its simplest of functions.”

“And what if it stood out like a sore thumb, or worse yet, trigger something that we can't possible anticipate? If that thing’s as dangerous as they say it is, we can’t just dispel the Scouting Eye willy-nilly. The best case scenario is that it was fonud out, and the worst case is...everything coming down…” Lera held out a Scouting Eye that she conjured up instantly like a tennis ball in her hands. However, she kept her firm grip over it.

“You don’t make suggestions without any ideas…so what are you thinking?”

Wu mirrored her movements with his hands up, and he conjured up a small sphere of Void Domain before pinching the table-tennis size black orb in between the Cast lines over his fingers, once again leaving behind only the tiniest gap for a strand of Wave to come out from the sphere, “This. Blow this up when you dispel the Scouting Eyes, and they all cancel out. Try it.”

Lera squinted her eyes, and she slowly pushed apart the inner Cast structure of the Scouting Eye before Wu slipped in his smaller black orb. The small orb barely fit in the opening before the Scouting Eye’s Wave lines surrounded it. Though the main body of the Void Domain sphere was a counter to any Wave, the substructure that governs the inner workings of that Cast was still based on traditional Cast-making techniques that they have learned and used before.

Therefore, if Lera combined the segment of the Cast that enables dispelling of the Scouting Eye with the activation of the Void Domain sphere, then the disassembling of the Scouting Eye will correspond with the simultaneous activation of the Void domain, resulting in no net movement of the Wave in that volume of space.

As she held onto the other end of the Scouting Eye through her book of Casts and injected a single pulse of Wave, the Scouting Eye vanished into thin air without making a single sound, as if it had never existed in the first place. They felt a brief stifling sensation from the Void Domain before it also went away.

A little bit of an overkill from a technical point of view, but it should work fine.

“Hm.” Lera tried to hide her impressed look before she reached her hand towards Wu to ask for another. He delivered it, and she stuffed it into yet another Scouting Eye she conjured from her book of Casts. With the ball in hand, she reached over the ledge and released it straight down.

All of the workers down below had gone into the deeper parts of the tunnel when Lera slowly piloted the Scouting Eye to tuck into the middle of another big sphere that was close to the top of the pile. Then, she slowly reoriented the light-sensing part of the Cast so as to get a good view of the cave passages leading deeper underground.

“Try to see if you can copy down the structure of the spherical Cast…” Wu asked, “If not, I will just write it down.”

“Good luck with that.” Lera turned her wrist as the projection showed by the Scouting Eye zoomed around and nearly caused Wu to puke due to the disorientation.

“Hey! You are just zooming it on purpose!”

Eventually, the group of twelve returned with grumpy looks on their face. Their clothes were dirty and wet, with the ones wearing grey having big patches of darker colors while those wearing white now were dripping in the dirt. They all looked miserable, though not fully despaired.

“So...” The workers in grey shirts put hands around the next pile of spheres, “Unless you give us actual chariot Casts to ride in, there’s no way we can spread these all over. I am sure you have come to appreciate its…explosive properties.”

“These are unintended detonations.” Another worker added as the men in white wiped away their face with sleeves that are equally as dirty, “So the closer we get towards actual detonation times, it will only become more volatile. There’s no hiding the true purposes of these things.”

“I shall relay the difficulties…” The men in white said finally, “I am sure we could come to an understanding that will satisfy her majesty.”

Wu and Lera looked at each other nervously, and they didn’t exactly like what they were hearing so far.

“For now, let’s just move as much as these Casts as we can.” The man ordered the rest of his guards to help the workers before he sat down at the back, “Don’t bother implanting it for now.”

“Very well.” The workers said before one threw his long wet hair behind him and his small eyes glanced casually at the gaps in within the spherical Casts before moving on, a short glance shared between the peeking Lera and him. They loaded up the one sphere where Lera’s Scouting Eyes was at into the cart before heading off into the darkness once again, leaving behind the one man who took a sit on top of a rock column and relaxed after trying to wipe away the dirt on his clothes to no avail.

There was the sound of a sharp whoosh from behind him before the man rapidly turned around in shock. He opened his mouth, but his entire presence was immediately swallowed up by Lera’s Void Domain as Wu looped his hands around the man’s throat and yanked him back with his legs kicking out in a frenzy.

“Tell me everything.” Wu said through his suppressed voice even as Lera had made sure that nothing could go past the small bubble of space that they are in, “What are your plans here?! What are you doing with those balls?!”

“Get...off...me!” The man growled, reaching his hands out and elbowing straight into Wu’s armor. Sensing that effort was futile, he then clenched his fist as a blade appeared in his hand before he swung up, the tip nearly stabbing Wu in the head when Wu manipulated the man's body through a sideways pressure and caused the attack to swing out wide before Lera knocked the blade away.

“Guess we will talk later,” Wu muttered as the man’s body stiffened like a statue with a little more pressure around his neck. Pressing a finger along his temple and knocking him out with a pulse of the Void Domain, he then stood with Lera who conjured up her chariot and lifted the two of them out of here.

All of that was done while the group of workers and guards were busy dealing with the second sphere, and by the time they made sure it’s stabilized and returned, their leader was nowhere to be seen, and they had simply assumed that he called it in early for that night.

In the meanwhile, Lera's Scouting Eyes detonated ever so briefly before its Wave was swallowed up by the Void Domain.