It was a scent Ken had never encountered before—not a cat's, not a dog's, nor that of any other animal he recognized. This did not strike him as strange. After all, his olfactory "database" was still limited, gathered mostly amid the chaos of the city.
So what kind of animal was it?
A flicker of curiosity stirred in Ken. And once his curiosity was aroused, he had to pursue it to its end.
He turned back on his phone's flashlight, picked up a stick, and began examining the rat's corpse.
The body was crawling with insects whose names Ken did not know. As he prodded them with the stick, they scattered under the beam of the phone's light—some burrowing into the grass, others disappearing into the soil. On the carcass itself, countless tiny maggots writhed and crawled.
In the past, such a sight would have made his scalp prickle with disgust, his stomach churn. Now, he felt nothing of the sort. He could even calmly focus on distinguishing the scents clinging to those insects, on the faint sounds produced by their squirming bodies.
From a cursory inspection, the rat had clearly been dead for some time, though Ken had no real knowledge of how to estimate an exact time of death based on the degree of decay.
He sniffed again, carefully. The strange scent that had caught his attention earlier—its source had already departed. It was no longer here. The trace was extremely faint, nearly dispersed.
There was a strong possibility that the source of that scent had been the predator that killed this rat.
What puzzled him, however, was that although the rat's death was gruesome, its body was largely intact. No limbs were missing. Its belly had been torn open, yet the internal organs did not appear to have been eaten. Had the animal that killed it simply found it displeasing? Or had it toyed with the rat, killing it out of cruelty rather than hunger?
Yet that scent was neither cat nor dog. Aside from cats and dogs, what animal would behave like this?
Ken took several deeper breaths, searching for the direction in which the scent might have left. After walking a few steps, he realized he could no longer trace it at all.
Perhaps too much time had passed.
Holding up his phone, he carefully illuminated the ground around the dead rat, scanning for any remaining traces—footprints, claw marks, anything at all. He searched until his phone battery was nearly drained, yet found nothing of value. Apart from his own footprints, there was no information he could discern—no information that he was capable of reading.
He turned off the flashlight and sat down nearby. Drawing in a slow breath, he relaxed his muscles, closed his eyes, and opened his senses, continuing to explore his surroundings through smell and sound.
Ken was not merely practicing. He was searching.
The scent that had drawn his attention filled him with curiosity. Even if he could not find its source, he hoped to encounter a similar scent somewhere in these mountains, to follow it, to determine what kind of creature had left it behind.
Every individual organism carried its own distinct odor, and every species or group possessed a characteristic scent of its own.
That peculiar scent from earlier had been mixed among countless others, subtle and easily overlooked.
Yet just as he was about to leave, he had detected it with startling precision—and been drawn to it. It did not exist in his "database." He had never smelled anything like it before.
It felt like an instinctive response, as though his body itself were telling him: this scent matters.
Ken remained seated in the mountains until sunrise, about five meters from the dead rat.
For an ordinary person, spending the night in a pitch-black forest—where one could not even see an outstretched hand—would inevitably provoke unease, no matter how brave they were. At the very least, they would worry about insects crawling onto them.
But although Ken's eyes were closed and he saw nothing, everything within a dozen meters of him was vividly clear. There—a worm burrowing through soil. There—an insect hunting its prey. There—a spider spinning its web. There—ants marching in formation… ah, and a beetle landing on his shoulder. He flicked it away with a finger.
Fortunately, mosquitoes seemed completely uninterested in him. Ever since his mutation, he had not been bitten once.
Throughout the entire night, that scent never appeared again.
Of course, sitting in one place meant he could not search the entire mountain by smell and sound alone, small as the mountain was.
So he rose and began to search.
The reason he had not done so the night before was simple: although his hearing and sense of smell far surpassed those of ordinary people—and he could walk familiar city streets with his eyes closed without issue—this mountain had no paths. He would likely have collided with trees or stepped into empty space after only a few steps.
By late morning, Ken had finished searching the entire small mountain.
At one o'clock in the afternoon, he finally left, jogged home, changed out of his filthy clothes, and took a shower. Then he went to the largest zoo in the city.
He could not quite let go of that scent. He had always taken the "signals" from his body seriously, no matter how faint they were, because they might help him better understand himself.
So he had not come to the zoo for leisure.
He had come to enrich his "database."
He wanted to see whether the zoo might contain any species that shared that scent.
After buying a ticket, Ken moved through the zoo methodically, passing every enclosure and every fence, collecting the scents of every animal.
Even animals that remained hidden inside their enclosures, never appearing in the outdoor viewing areas, could not escape his detection.
By six in the evening, when the zoo was about to close, he had carefully distinguished the scent of every animal within.
Regrettably, none of them belonged to the same category as the peculiar scent he had detected the night before.
This only deepened his curiosity.
After returning home, he grabbed a flashlight and headed once more for the small mountain, unerringly locating the dead rat again.
It was already past eight in the evening. With a flashlight in one hand and a small wooden stick in the other, Ken examined the carcass once more.
The decay had progressed further, but he still discovered two penetrating wounds—marks that looked as though they had been made by claws.
Yet those claws must have been as thick as his index finger.
A large feline?
But that could not be right. He had smelled tigers, leopards, lions—every large cat in the zoo. None of their scents matched.
Besides, this was neither deep wilderness nor an undeveloped region. Such beasts could not possibly exist here. At most, there might be feral cats or dogs.
And even if some large carnivorous predator had been hunting here, there would not be only a single dead rat. There should have been more traces—something he could find. More importantly, there were no footprints near the rat at all. That alone defied common sense.
Ken searched the small mountain and the lakeside around it for the entire night, yet found nothing. Not a single trace of that scent.
At dawn, he climbed the mountain again, using the dead rat as the center point and conducting another meticulous search of the surrounding area. He continued until after five in the afternoon, but still found no clues—no sign that any fierce beast had appeared here.
Ken began to wonder whether he was being overly obsessive.
Perhaps that scent had simply been too close to vanishing, and his judgment had been flawed—a misreading of his own senses.
As he entered his apartment building, he ran into Miss Yang, the woman who owned a husky, striding out of the elevator. Her brow was tightly furrowed, her expression anxious.
She did not acknowledge Ken, and Ken, naturally, did not greet her. They passed each other as though the other did not exist.
But after Ken pressed the button for his floor inside the elevator, Miss Yang suddenly turned back and blocked the elevator doors.