The "Ghost Signal" in the dense mountain forest was initially a story my comrades in the communications squad used to tell, meant only to scare ieley Yang. Unexpectedly, beneath the wreckage of the American C-type transport plane we just found, a signal coded with death emanated with startling clarity. However, calling it the legendary "Ghost Signal" might be slightly inaccurate. "Ghost Signal" specifically refers to faint, mysterious waves received through the radio frequency, whereas this sound was clearly not a radio signal, but a conventional material signal originating from within.

The primordial forest before dawn was cloaked in the dark shadow of death’s wings; there wasn't a whisper of wind or the rustle of leaves. It was so silent you could hear a pin drop. I sat in the treetop, listening several times; there was absolutely no mistake—repeated, over and over again.

The fat man beneath the tree also heard that strange series of "di-di-da-da" signals, craning his neck to stare up at the canopy. Because I was situated in the middle of the crown, I discerned that the sound’s source wasn't the cockpit at the very top, but rather the spot where the aluminum wreckage of the transport plane met the trunk of the two ancient, husband-and-wife trees.

Since we had no understanding of the mysterious phenomenon known as the "Ghost Signal," and given that the living naturally harbor some trepidation toward things originating from another world, we hesitated to act rashly. We only switched on our "Wolf Eye" flashlights, aiming the beams at the source of the sound. The more we looked, the more unnerving it became; even the strangely shaped old bark seemed, in the darkness, like menacing, grimacing corpses.

I quietly asked ieley Yang beside me, "Could it be an American pilot fell into a tree hollow? And the distress radio waves he emitted before death still echo ghost-like around this great tree?"

ieley Yang shook her head. "Impossible. When I searched inside the wreckage earlier, I examined every inch. There weren’t any remains of the crew, nor any parachutes. That’s why I concluded they bailed out before the crash, and since the nose hit the mountain and was utterly destroyed, this section of the fuselage fell onto the canopy. How could that signal possibly be coming from inside the trunk?"

I turned to ieley Yang. "Before you shot down that Great Horned Owl earlier, that sequence of signals paused for a bit, then suddenly turned to DED. Is there a connection? Besides the U.S. Air Force piloting this C-type transport, who else in these deep, wild mountains understands Morse code?"

ieley Yang didn't share my spectral experiences, but she wasn't entirely materialistic. She had mentioned to me more than once that after death, people go to heaven, which is the true destination of life's journey. So, from that angle, ieley Yang believes in the existence of souls. ieley Yang told me, "Perhaps I misheard the initial distress code; it was probably the owl pecking at a tree lizard inside the fuselage, making it sound chaotic and disjointed. But this current signal you heard is entirely different; its timing is very regular. And it has repeated so many times without error..."

Hearing it with my own ears, emanating from the nearby tree trunk, and so clearly, I had no choice but to believe the legend of the "Ghost Signal" held some truth. I said to ieley Yang, "Although the signal sound is rhythmic, it doesn't sound like a mechanical signal; it’s somewhat like the sound of dripping water, but much more muffled. Perhaps our guess is right—there's a dead person inside the tree..."

ieley Yang replied, "Scientists have experimented; the electrical waves generated by the human soul should be below 7V. Even such faint energy could potentially be preserved for a long time in specific environments or magnetic fields. But right now, the most important thing is, what intention is this death code conveying? Is it a warning to us? Or a threat?"

Based on my experience, when faced with a situation like this, choosing to simply evade is never the right path. It leads to paranoia, confusing every shadow for danger, which in turn utterly disrupts one's composure, making an accident all the more likely. The only way to truly settle our minds is to bravely find the source and uncover the truth. Besides, the sky is about to lighten; night will soon pass, and once it's day, there will be nothing to fear.

So, I pushed myself up, steadying myself on a branch, and said to ieley Yang, "Guessing won't help. Let's go take a look. We’ll see exactly what spirit is haunting this place and then decide how to deal with it."

ieley Yang nodded in agreement. She swapped the "Chicago Typewriter" in her hands for a fresh magazine and handed it to me; that submachine gun was too heavy for her to handle comfortably. We both adjusted the focus of the headlamps on our climbing helmets and checked the safety of our climbing ropes to ensure they were secure.

I pulled the magazine out of my submachine gun, confirmed it was fully loaded, and tapped it twice against my helmet with a sharp clang. This model was notoriously prone to jamming, so it was crucial to seat the rounds tightly to prevent a malfunction at a critical moment. I reinserted the magazine, chambered a round by pulling back the bolt, waved at ieley Yang, and we separated, climbing the branches of the old tree in opposite directions, tracing the source of that "Ghost Signal" toward the junction where the fuselage met the canopy.

Because the surroundings were so still, the closer we got, the clearer the "di-da" sound became. The more we listened, the less it sounded like an electronic tone. After a careful search near the wreckage, the beam of our helmet spotlights finally converged on a section of the tree trunk. To prevent any sudden mishaps, ieley Yang positioned herself slightly ahead, while I stayed half a meter behind her to provide cover. Illuminated by the spotlight, ieley Yang confirmed the sound was definitely coming from this spot—an unusual "drip-drip-tap."

I aimed the barrel of my Thompson submachine gun at the target, just in case something like an owl popped out to attack her. If anything went wrong, I would pull the trigger without hesitation. The .45 caliber of the "Chicago Typewriter" was no joke; its machine-gun-like rate of fire could shred any jungle beast into pieces.

Seeing I was ready, ieley Yang took out her Russian-made "Paratrooper Knife" and held it ready. She aimed at the section of the trunk completely overgrown with vegetation and began to cut slowly, peeling away the thick layers of green moss and vines. After only a few cuts, she discovered it was a natural tree hollow.

The hollow was only as large as two fists put together. Over the years, the opening had been completely sealed by the parasitic plants growing on the tree. If you didn't break through this natural camouflage, it looked indistinguishable from the rest of the trunk—bumpy, uneven, and covered in green moss.

The parasitic plants were incredibly dense and thick, layered upon one another. Some were so badly rotted that when peeled away, they turned into green sludge, difficult to clear entirely right away. ieley Yang carefully inserted the tip of the "Paratrooper Knife" into the deepest part of the moss. The sensation transmitted through the tip felt like striking something hard.

ieley Yang and I exchanged glances, both filled with questions. We hadn't anticipated such a small hollow here beforehand. Even if there were a hollow, for a person or animal to make a sound inside, it shouldn't be this small. There were countless such small apertures on this ancient pair of banyan trees, holes just big enough for a squirrel. But there are no squirrels in this forest, so we could completely rule out squirrels messing around inside. A tree lizard, which is slightly smaller than a squirrel, is a very quiet animal and could certainly not be making this noise.

Furthermore, judging by the thickness and degree of decay of the moss and parasitic plants on the tree, they couldn't have formed in a short time. As I was about to look closer, the trunk behind me shook violently. It turned out the fat man had climbed up for the second time. This time, without my prompting, he immediately secured his safety harness.

I was about to ask him why he wasn't keeping watch below, but then I saw the panic on his face. Few things could frighten the fat man. I heard him stammer nervously, "Old Hu, dammit... this forest is definitely haunted, I have to stay with you guys. That last thing scared the hell out of me!"

Seeing he wasn't joking—and short of money being involved, only things that directly threatened his life made him tense—I quickly asked what happened and if he saw something.

The fat man composed himself slightly and said, "I was under the tree just now, looking up at you two scrambling in the canopy. But it was too dark, and I stared for a long time, only seeing the hazy lights of your helmets. I got bored and decided to light a cigarette to relax, when suddenly I heard a woman crying nearby, such a miserable sound. Damn, it terrified me! I held the cigarette backward and nearly burned my tongue. There’s definitely a female ghost! Listen... listen... here it comes again."

ieley Yang had just been using the "Paratrooper Knife" to scrape away the rotted vegetation from the tree hollow. She hadn't yet seen what the hard object was, but hearing the fat man mention a crying female ghost nearby, she stopped working and, along with me, strained her ears to listen to the surrounding noises.

We had only been paying attention to the "Ghost Signal." Now, as we quieted down, we could indeed hear intermittent whimpering sounds. There was no wind behind Mount Zhelong, so it couldn't possibly be the wind. The sound was exceptionally tragic and shifted erratically, sometimes from the east, sometimes from the west, making one’s skin crawl even more in the pitch darkness.

The fat man, ieley Yang, and I immediately formed a staggered line in the canopy. I held the Thompson submachine gun, the fat man gripped his "Jianwei" air rifle, and ieley Yang leveled her Type 64 pistol. This arrangement condensed our defensive arc to about 120 degrees, providing mutual support.

The mournful crying circled us twice, then suddenly split into three distinct sounds, rapidly descending upon us from mid-air. This time I heard it clearly: it wasn't a female ghost; it was the screeching of night owls—the kin of that damn owl we shot. But this time, there wasn't just one or two; judging by the calls, they weren't small individuals. They must have come for revenge. Even though we were armed with guns and ammunition, facing these phantoms of the night sky in the darkness put us at a distinct disadvantage.

At this point, ieley Yang couldn't worry about conserving illumination flares anymore. She fumbled in her pouch and pulled out a signal pistol. With a thump, a flare shot up from the top of the giant tree, hanging in the sky like a pale white sun, taking a long time to dissipate. The surroundings were illuminated as if covered in snow.

We were both suffering from headaches caused by the intense white light of the flare. Just as we were enduring the glare and preparing to scan for targets to shoot, the forest suddenly fell into a deathly silence. Everything vanished except for our heartbeats and breathing.

The suddenly attacking owls, startled by the flare's light, retreated into the distant darkness, disappearing without a trace. And that hair-raising "Ghost Signal" sequence vanished with them; not another sound could be heard, not even the usual morning chirping of birds. It was as if all the animals had died off.

Before I could wonder about it, almost simultaneously with the vanishing sounds, the horizon revealed jagged cloud peaks, and a streak of dawn broke through the gap, casting the first ray of morning light into this bizarre jungle.

It seemed that at the very instant daylight arrived, all the ghouls and monsters in the valleys and jungles fled back to their lairs to escape the sun.

We remembered the hole in the tree and turned back to look. On the trunk beneath the C-type transport plane, there was a green aperture. Deep inside, something like a smooth, deep red stone gleamed faintly in the morning light, its outer layer of moss having been scraped away by ieley Yang's knife.

Before I could grasp what was happening, the treetop beneath our feet suddenly cracked and splintered—kacha-kacha-kacha. It turned out this thick, lateral banyan branch had borne the majority of the C-type fuselage's weight. Because we had clustered together in urgency to prepare for the attacking owls, the weight was too concentrated—a major taboo when moving in trees. Now, with the weight of three people, especially the fat one, this old banyan, already severely lacking in nutrients, could no longer support it. The majority of the upper trunk split in two; the ancient structure completely snapped.

Fortunately, all our safety ropes were secured to the main trunk of the old banyan. Though we were jolted against the tree trunk, we thankfully didn't crash directly to the ground. This safety rope had saved us no fewer than three times today. The C-type transport plane overhead, having lost its primary supporting branch, slid directly down below the towering tree, letting out a massive and tragic crash.

Looking up, we could see the interior of the cracked trunk. We all stared dumbfounded. After a long pause, the fat man finally said, "What in the world is that? It looks valuable... I think... we've really... really struck it rich this time."

At that moment, that familiar yet alien signal sound suddenly flashed out again from the split trunk...