The McKinnley household was, for the next few minutes, fairly chaotic.

Nathaniel was attempting to move people upstairs, further from the source of dark mana. Thanks to Vance, they'd been able to detect and, with some confidence, determine that this concentration of dark mana was largely harmless to them. Coupled with the fact that, other than Vance, nobody had experienced any dark mana related problems after spending two nights in its presence, Nathaniel wasn't in a hurry to leave the house.

Nicholas, on the other hand, was keen to investigate. While the two of them were bickering about their next immediate step, Vance turned his focus back on the source. He followed its movements as it travelled in a curved path beneath him. Vance had never really considered using his mana sense to look underground. Now that he was doing so, he found that it was quite tricky. The abundance of material made it difficult to judge distances and compositions with much accuracy. In this case, dark mana stuck out like a sore thumb.

The path it followed was snaking and went back on itself as if moving through some nonsensical tunnel system. Eventually, it began to reach the edges of Vance's mana sense.

"Should I follow it? I won't be able to keep track of it for long from here." Vance asked in Nathaniel's direction.

"Yes!" Nicholas answered before Nathaniel could get a word in.

"Nick," Nathaniel said pointedly. A few seconds of quiet passed and Nathaniel sighed loudly. "Though you're right, this is the only lead we've had. It'd be stupid of us not to capitalise on it. That being said, we're tired and not prepared to confront whatever is going on. I'll go with Vance to see how far we can follow this thing. At the first sign that it's closing on us even a little, we're leaving."

Vance was surprised. He didn't expect Nathaniel to actually take him up on his offer. Vance stood with renewed vigour and pointed towards the back of the house. Vance noticed the source moving in a more direct line than it had in a while and realised they were against the clock.

"It's heading that way. We don't have much time." Vance began to make his way towards the rear of the house, trying to keep his sense locked on the source for as long as Nathaniel needed to organise things. He was starting to get used to that feeling of emotional distress that seemed to come with sensing dark mana. Vance had learned long ago that he wasn't really physically experiencing the things he felt with his mana sense. For example, sensing fire mana and the associated feeling of heat wouldn't actually burn him. Dark mana was a little different in that the feelings were more based on emotion rather than pure sensation. Even so, he was slowly beginning to learn to differentiate his feelings from those thrust upon him.

"Nicholas, you wait here. I need you to make sure these two stay safe."

"You've got to be kidding, right? My son is out there! I-" Nicholas began to raise his voice, but Nathaniel cut him off before he gained any real momentum.

"Nick! We both know I'm better equipped for this. I know you want to come but remember that we're not going to confront whatever this is. Not yet."

Vance was in the next room by this point. Even at this distance, he could swear that he could hear Nicholas' teeth grinding together. He moved far enough away that their voices turned to murmurs and then, a few moments later, Nathaniel was by his side.

"Ready?" Nathaniel asked.

"Yes, this way."

Like this, the two set out into the dark, quiet night. Nathaniel took the lead, taking verbal instructions from Vance. They headed into the grounds, then out further into the city. Nathaniel made good use of his mastery over wind magic to help them scale the wall at the edge of the estate. Vance held on to Nathaniel, who took the role of guiding them through the city streets while Vance kept his focus below. It was slow going, as the source took a long, winding path that often went back on itself, this pattern did not change until, after they'd been following along for about an hour, Nathaniel brought them to a stop.

"Why are we stopping?" Vance pulled his attention upwards for a moment, surprised.

"Because we've reached the city walls."

"Where's the closest gate?"

"I don't think it's a good idea for us to continue."

"You're kidding, right? We need to find out where it stops, otherwise, we won't know where to investigate tomorrow, what if-"

"Vance. We're not dealing with some thug or thief, here."

On the way here, Vance had allowed himself to think about the ramifications of their current exercise. If they were successful, and a little lucky, they might find some information to help them investigate Niall's disappearance and the surrounding demon activity. Even without that, there's a good chance they'd discover something capable of threatening the wellbeing of the locals. Both of these things were appealing to Vance and he'd become somewhat obsessed with the resolution. After Nathaniel's gentle reminder that there was a non-zero chance it was, in fact, a demon, Vance took a moment to stop and think. He took a deep breath.

"Right, sorry. I got carried away. You're the expert here, what do we do now?"

"We know its direction, rough mode of travel and pace. If this is a demon, then we don't want to let it know that we're onto it. Instead, we're going to want to investigate the hours where we believe it to be absent. I'm probably going to need your help with that. How are you doing, by the way? You must be tired by now."

"I'd be lying if I said I wasn't. I think I can keep this up for another hour or so."

"Seems like all of your practice is paying off." Nathaniel patted Vance on the back. Almost on cue, Vance finally lost track of the dark mana source as it left the range of his mana sense.

Vance scratched at his chin for a moment as a thought came to him, then he experimented with his mana sense. He pushed it into the earth and focused as much of his attention as he could at the depth where he'd been following the source. He started paying close attention, looking for naturally occurring wind mana. He found that this particular form of mana was one of the more difficult aspects to detect.

"Something wrong, Vance?"

"No, I'm trying to see if there's any natural wind mana down there. If it's open to the air, then there might be a breeze. All of the ground in between is making it really hard to tell. Not to mention there's natural wind mana in tiny amounts all over the place. It's like a needle in a haystack. I think I need to be closer. There's plenty of earth, water and even a little metal mana but it's all a mess."

"There's an intersection not too far from here which has lower ground. I remember it flooding a few years back, I think we just went past it. I don't think it's that low, but it might help."

"I'll take what I can get, lead the way."

A few minutes later, the two of them were standing in the aforementioned intersection. Vance found that this place reminded him of home a little, namely due to the horrible state of the cobbles here. He cast his mana sense around and let it wash over the area for a few minutes, then noticed that behind one of the buildings nearby, out of sight of the street, there was an old, broken well.

Vance moved over there straight away, beckoning for Nathaniel to follow.

"We can use this," Vance said, excitedly.

"I like what you're thinking." Nathaniel walked straight up to the well and started moving some of the clutter that had been accrued at the top of it. Then, Vance made his way over and gave his best efforts to dislodge some of the old stones. To his delight, they were still sturdy. The two of them cut quite the interesting sight, ransacking an old well at stupid-o'clock in the morning. Vance then hoisted himself up onto the side of the well and hung his legs over. There was no rope, nor bucket, nor winch remaining on the old thing.

"Ready when you are," Vance said, smiling at Nathaniel, who proceeded to conjure an enormous amount of wind mana, which he used to cushion the air beneath Vance.

"You've got about a minute, then I'm flinging you out," Nathaniel said confidently before lowering the cushion of air slowly. Vance stood atop the cushion and rode down into the well. He descended a few meters, then signalled for Nathaniel to stop. Vance took a moment to be amused by the fact that standing on an invisible cushion of air, investigating the bottom of an old, ricketty well was, as things went, not that weird for him anymore.

At the bottom of the well, there was a small groove in the stone that still contained a small puddle of water and Vance could sense the slow dripping of water mana in from one of the sides. Now that he had a proper point of reference, he plunged his mana sense into the dripping crevice and followed it along. It travelled upwards a little, then widened. In this more open space, he could sense several other cracks and crevices that went in different directions, though he couldn't cover enough distance to see where they led. More importantly, he could sense moving, natural wind mana.

True to his word, almost as soon as Vance made this discovery, Nathaniel brought the cushion of air upwards and ejected Vance from the well, depositing him safely on the ground. Unconsciously, Vance had been holding his breath down there, now that he was out, he took a long, deep breath before speaking.

"I think it's travelling using some sort of subterranean river system. There's a maze of tiny cracks down there, could lead all over the place, but it does open out to air at some point and probably quite a lot of it. There was a breeze strong enough for me to notice the wind mana displacement."

Vance pointed in a direction, gesturing towards where he'd detected the larger open area.

"Excellent work." Nathaniel sounded genuinely pleased and brushed a few lingering cobwebs off of Vance's clothes. "Let's head back and tell the others, I think that's enough adventures for you today."

"If you want, I could probably map out the tunnels. It'd take a while but-"

Vance was positively beaming. For a long time, he'd wanted to be useful to the McKinnley family, especially Nathaniel. His little taste of success here ran straight to his head. For most of his life, he'd been the one to need help. Now, whenever he was needed, he found the feeling to be quite addicting.

However, ever the voice of reason, Nathaniel put a stop to Vance's sprint towards inevitable exhaustion, or worse.

"Vance, you've done more than enough. Let's get you some sleep for now and you can leave the rest of this to us for now. If we need you, we'll come and get you. Mapping these things out is an excellent idea, but you'll never finish that tonight. Besides, you might start making mistakes if you get too tired, best to have you fully rested."

Vance felt some of the energy drain out of him, but he didn't argue.

"That's true enough...what about you?" Vance asked, a little deflated.

"Oh, I'm going home too. I'm going to send out a few messages, but I'm still going to be the one to handle this. Nick will help, too, as well as some of the masters from the college."

Nathaniel put both hands on Vance's shoulders and lowered himself as if to meet Vance at eye level. Vance was well aware of the futility of the gesture, but something about it did feel nice.

"I don't want to understate this, you've given us what we need to move forward in an investigation that could save one, or many lives. If this happens to be the demon that we've been looking for, then there'd be no doubt that I made the most fortunate decision of my life by bringing you into my home. You're young, so I don't expect you to fully understand the ramifications, but believe me when I say that you've already contributed more than I could have asked for."

Vance's head lowered a little and he failed to control the smile creeping onto his face.

Nathaniel let go and straightening himself up a little, then added. "Besides, magic capable of locating things at a distance without prior preparation of the target is incredibly hard to come by. I always knew you'd be a valuable investment."

He began walking off, back towards their home, leaving Vance to follow behind. Vance was grateful that Nathaniel went ahead. That way, he wouldn't be able to see the tear rolling down his cheek.