Igor gathered some stones of varying sizes and neatly placed them on the ground. He then took out a water bag and went to a nearby stream to fetch water. Igor had spent quite a long time roughing it on Guru Mountain, experiencing many strange things. Yet, this water bag remained unscathed and never lost. That was a small miracle in itself.

He filled his water bag with just a little water, as he planned to use these items for some tests.

The only way to determine whether his conjecture was correct was to experience it for himself. Kadi was not Igor, and he could not verify the hypothesis for him. Similarly, Kadi's experiences were not something Igor could feel. He had not reached a state of Spirit Empathy yet, as his Spirit Sensing hadn't reached High Rank. Back in Ghost Wind Valley, it was astonishing that he had managed to connect his Spirit Power with Kadi's. That experience had marked the peak of his Spirit Sensing, reaching the level of Spirit Connection—the very limit of his ability.

The difficulties were many, but retreating because of them was neither Igor's style nor Kadi's. Igor loved to solve problems, even if he sometimes looked foolish. Kadi, who wasn't one for overthinking, was as stubborn as an ox; he wouldn't turn back until he reached his destination.

Overcoming these difficulties was something Kadi and Igor had to face at that moment.

"Kadi, do you remember what you heard or saw each time you were nearing Moonflow Stream?"

"The situation was different each time, and I can't remember everything right now!" Kadi exclaimed, scratching his head. A familiar wave of anxiety washed over him; every time he had to think hard, he felt this way.

"Hmm... this might make things a bit difficult." Igor scratched his head. According to Kadi's description, finding the factor that triggered the sound in Kadi's ears was indeed challenging.

This vast mountain emitted millions of sounds and presented countless scenes. How different was finding one among countless others from trying to scale the sky?

I'll just have to slowly eliminate possibilities, Igor thought. Anyway, I've come this far; a little more complexity won't hurt.

Igor looked at the stream beside him. Water rushed over the stones, flowing down through the crevices, aided by the mountain's height. The black stones looked as if they were covered in white flowers—a beautiful sight!

The first sound Igor ruled out was that of flowing water. Not because it was too common, but because it was too frequent; it couldn't have induced the ballads.

If the sound of flowing water were the trigger, Kadi should have heard Moonflow Stream's songs long ago...

Having dismissed the sound of water, Igor also ruled out the omnipresent sound of the wind, the rustling of leaves hitting each other, and the sound of rolling stones.

There were too many sounds to eliminate. If these common, everyday noises were the cause, Kadi's ears would never rest; any sound could trigger the singing.

Eliminating these common sounds didn't bring Igor the slightest relief. There were so many sounds; trying to pinpoint the trigger through elimination was an enormous waste of time. They didn't have much time to spare. Not to mention, back in Ghost Wind Valley, they had inexplicably lost a period of time, which was already a major headache for Igor.

It must be a sound that triggers the trap, Igor mumbled to himself. Other factors aren't as direct as hearing; using other sensory stimuli would just waste Spirit Power. He was still stuck on the process of elimination. Although he had a general idea, many details of his reasoning were still flawed.

"What did you say? You're speaking so softly." Kadi felt his brain wasn't up to the task. He desperately racked his memory for details from their previous failed attempts, hoping to find something to help Igor. But his memories were too fragmented, and he couldn't unearth any useful information, which only added to his frustration.

This Moonflow Stream is so strange, Kadi thought. When I'm not looking for it, I always hear its songs out of nowhere. Now that I'm standing right next to it, I can't find any way to cross.

Behind Moonflow Stream was a small peak of Guru Mountain. This small mountain had no notable features and was very ordinary. It wasn't as wide as Dawn Peak, nor as magnificent as Grey Eagle Peak. It was as average as the many other small hills surrounding it.

This small peak was what had them trapped. It blocked their path; they couldn't get past it, nor could they find a way to climb it. This was the biggest obstacle to figuring out how to cross Moonflow Stream.

Igor decided to set that problem aside for now; it could be addressed later. They would only have a chance to tackle it once they had solved the immediate issue.

Moonflow Stream was right beside them, but looking forward, backward, left, or right, there was no discernible complete path. The small hill seemed the same on all sides. For now, they could only choose to go around it. However, there was a downside: the farther they walked, the farther they would stray from Moonflow Stream.

"Have you figured something out?" Kadi, despite being the one directly affected by the problem, tilted his head and waited nonchalantly for Igor's answer.

"The stones I gathered earlier... I thought they'd be very useful, but now it seems they're just a burden."

Upon hearing Igor's words, Kadi looked down at the stones on the ground. They were now neatly stacked by Igor, resembling a small fortress.

"Did you build a mountain?" Kadi rubbed his nose, asking curiously.

"A mountain? I was just stacking them randomly." Igor was straightforward; he could have maintained an air of mystery in front of Kadi but chose not to.

"Oh, have you thought of something then?"

"I haven't thought of anything." Igor remained calm. Worrying now was useless; he might make a breakthrough if he just calmed down and thought deeply.

Igor had a habit when thinking: he couldn't stay still. Sometimes he would pace back and forth or rub his hands together. This time, he chose to stack stones.

Originally, he wanted to try hitting the stones or directly pouring water on them for some experiments. He wanted to see whether it was these two sounds that awakened that thing in Kadi's ears.

But after eliminating the sounds of wind, flowing water, and falling leaves, he also ruled out those two possibilities.

The reason was simple: if it were those sounds, Kadi's ears wouldn't get any rest.

Then, it hit him!

"Kadi, you said that every time you were nearing Moonflow Stream, you heard the song, right?"

"Yes. It happens every time. Just as I'm about to get close, the song starts…"

"Did you hear this sound first?" Igor picked up the water bag and—SPLASH!—poured its contents onto the neatly stacked stones.

"Yes, that's the sound! Holy cow! The singing has started again!"