Hearing Fatty mention the discovery of the entrance to the Worm Valley, Shirley Yang and I both raised the binoculars hanging around our necks and looked in the direction he indicated. After adjusting the focus, we saw a vast expanse of wild flowering trees, yellow and white, at the foot of the distant slope, with swarms of golden Swallowtail butterflies darting among the blossoms. These butterflies were quite large, flying in clusters, never straying far from that patch of flowering trees.

Shirley Yang exclaimed, "Those flowers must be Phalaenopsis orchids, I never expected them to attract so many Golden Swallowtails... and Gold-striped Swallowtails... even the rare Golden-lined Great Peacock Butterfly. It’s like the golden leaves of the Tree of Gold blown by the sea wind in the Garden of the Gods in the Aegean Sea from ancient Greek myths."

I know nothing about butterflies. I peered through the binoculars for a long time, but apart from the butterflies and the wild flowering trees, I could see no terrain resembling a valley or a ravine. The vegetation layer here was too thick; all the topography was completely concealed, making it impossible to discern where a valley was or where a stream flowed. Looking down from above, it was nothing but a succession of rises and falls, entirely covered in the dense flora characteristic of the Tropic of Cancer region. What appeared higher wasn't necessarily higher ground, but rather uneven plant growth. This primary forest was significantly different from the familiar Greater Khingan Range primary forests we knew.

As the saying goes, "The tree that stands out in the forest is the first to be blown down by the wind." In the Greater Khingan Range, the canopies of the trees are relatively uniform in height, allowing them to collectively resist strong winds. Here, however, it is a place where two rivers and three mountains intersect. The basin valley in the middle is low-lying. Furthermore, due to Yunnan’s consistent climate, lacking distinct monsoon seasons, the lower the elevation, the more severe the dampness and humidity become. Temperatures remain around 25 to 30 degrees Celsius year-round, and wind might not blow even once a year. Consequently, all sorts of plants grow unchecked. Underground water resources are abundant, and the air humidity is extreme, allowing plants to grow as tall and dense as they please without restraint. This results in tall, intertwined woody vines, epiphytes, and herbaceous climbers growing to varying heights according to their specific characteristics, creating a rugged, uneven tapestry. The tallest are the famous Dendrocnide excelsa (Wish-to-the-sky trees) of Yunnan. Normally, such massive trees are only found south of the Tropic of Cancer, but the unique environment in this mountain hollow allowed quite a few sky-scraping Dendrocnide excelsa to flourish.

Only a few of the larger pools of water were uncovered by vegetation. Many deep, secluded areas were shrouded in swirling mist, making it impossible to discern anything from a distance. We certainly couldn't plunge into the forest based solely on a few clusters of golden butterflies. The complexity of this environment defied common sense.

The human skin map was drawn during the Han Dynasty, two thousand years ago by the time it reached us. The topographical features marked on the map had changed drastically by the present day. Apart from certain specific markers and locations, the human skin map could no longer be used for precise cross-referencing with the forest below Mount Zhelong.

According to what the Blind Man said, decades ago, that group of Xie Ling strongmen entered the Worm Valley carrying crude explosives. They encountered large swarms of butterflies just before the ravine formed by the Snake River—which is the Worm Valley—but who could guarantee that butterflies wouldn't appear elsewhere outside the Worm Valley? Therefore, we couldn't definitively conclude that the entrance was there yet; we had to find the other location the Blind Man mentioned. Within the Worm Valley, there was a section of ruined wall—an ancient structure built by human hands along the Snake River, seemingly a dam used to divert the water flow while constructing the Tomb of the Xian King in the lake. After the Xian King was interred, it was demolished, restoring the Water Dragon Swirl in front of the tomb.

Only by finding that ruined wall could we use it as a reliable reference point to confirm the location of the Worm Valley. The safest approach was the same as that group of Xie Ling strongmen decades ago: after exiting Mount Zhelong, instead of entering the forest immediately, we should follow the mountain range’s orientation northward to locate the Snake River, a tributary of the Lancang River. Then, tracing the Snake River into the valley would ensure we didn't stray into the wrong path, making the navigation absolutely foolproof.

Fatty proposed an alternative: to relocate the artificial canal within Mount Zhelong and follow the ancient river course to find the Snake River. However, due to heavy rain in the upper reaches of the Lancang River, the waterways in Mount Zhelong had become an intricate network of interconnected small and large streams, possibly even diverting underground. The old riverbed was completely covered by vegetation and soil, rendering Fatty's suggestion impractical.

The three of us conferred briefly and checked the time: 3:30 PM. We had been moving since around 9:00 AM when we entered Mount Zhelong by raft and hadn't rested at all. We decided to use our current location as a relay point, rest for twenty minutes, and then head north, aiming to find the entrance to the Worm Valley before sunset. We would set up camp there and enter the valley first thing in the morning.

We found a relatively level slope to sit down and had some dried meat jerky to stave off hunger. But then Fatty started talking about those piranhas, recalling the mountain pools full of bright red blood, comparable to the blood pools in hell described in legends, which killed my appetite. Suddenly, a chilling thought struck me: what if those schools of fish, whose teeth were sharper than saws, had also swam into the Snake River? With those creatures in the water, it would be impossible for us to access the Xian King's tomb from below the water.

Shirley Yang said, "There is absolutely no need to worry about that. When I worked as a photojournalist for a geography magazine, I read a lot of material concerning wild animals and plants. The Sarcoprionyx (Knife-toothed Viperfish) exists in the waters of Asia, specifically in India, Myitkyina, Laos, and in the Americas within the region near the Tropic of Cancer, at around 20 degrees latitude."

Ancient India had the most occurrences. Buddhist scriptures record a great disaster caused by the Sarcoprionyx during the reign of King Ashoka. It was a time of a once-in-a-century flood of the Ganges River when an underground river from the Eastern Ghats Mountains poured into a nearby city, resulting in countless people and livestock being devoured by the fish.

The ancestors of these Knife-toothed Viperfish can be traced back to the aquatic Tiger-toothed Chasmichthys from the post-Ice Age period. Those fish lived in the ocean and possessed bioluminescent organs. Swarms of Tiger-toothed Chasmichthys could instantly kill the ocean's overlord, the Leviathan. Later, due to the great deluge of the subsequent glacial period, these creatures were cruelly eliminated by nature, and their descendants, the Knife-toothed Viperfish, evolved into freshwater species.

Although the Knife-toothed Viperfish are formidable, they have a major weakness. These fish can only survive in relatively cold water. Near the Tropic of Cancer, only the cold waters within solution caves are suitable for their survival. In those waters live a type of eyeless, hard-shelled shrimp, which exist in large numbers, but it's still not enough to feed the Knife-toothed Viperfish, leading to frequent infighting. Among the massive population of Knife-toothed Viperfish, only one percent survive until the final spawning season after September each year.

The spawning season for the Knife-toothed Viperfish occurs during the full moon of the Mid-Autumn Festival. Although they cannot survive in overly warm areas, they inhabit the warmer regions near the Tropic of Cancer specifically to breed in the warm waters at the end of their cycle. Immediately after spawning, the Knife-toothed Viperfish perish. The eggs, incubated in the warmer currents, develop into fry and then swim back to the colder waters to continue surviving. It is currently late June, which is the most active period for the Knife-toothed Viperfish; it is rare to see such large numbers of them otherwise.

Furthermore, because the Knife-toothed Viperfish have high demands on their living environment and require immense amounts of sustenance, signs of gradual extinction have emerged in recent decades.

Most importantly, this season is not the spawning period, so there is no need to worry about them migrating out of the caves now. However, returning will require extreme caution. Due to recent heavy rainfall, the waterways in Mount Zhelong have become a fully interconnected water network. If we return the same way we came, we might run into them in some section of the cave river system.

After hearing Shirley Yang's detailed explanation of the Knife-toothed Viperfish, Fatty and I were slightly relieved. We decided to worry about the return journey when the time came. Fatty felt he had shown weakness just now and wanted to regain face, so he told Shirley Yang and me, "How much trouble can these stinking fish cause? The only reason I felt they were a bit... you know, concerning, is because the Chairman once taught us to take the enemy seriously in tactics."

Shirley Yang said, "These fish are not the main concern. I keep thinking about the mummified figures suspended upside down in the river channel; their purpose seems to be more than just feeding pythons... but the Thao magic is incredibly strange, truly inscrutable. Fortunately, a random swarm of Knife-toothed Viperfish appeared, otherwise, it's hard to say what might have happened. Having already encountered so many troubles before even entering the Worm Valley, we must proceed step by step, cautiously."

I nodded and said, "This tomb is famously hard to take down. Since we are here, we must use everything we've learned to compete with it." I patted the back of my neck and said, "If only for this, we have to risk our lives for this big gamble."

Shirley Yang and Fatty both looked grim. This time, tomb raiding was an action directly related to survival. Riding a horse off a cliff allows no retreat; success is the only option.

We rested for a while and took out the contour map of Mount Zhelong—this map was extremely basic with significant errors. We zeroed the compass, re-established the altitude and bearing, corrected the map, marked the direction of the exit, and the three of us continued our journey to find the Snake River.

The Lancang River basin is vast, running from north to south, traversing the entirety of Yunnan, and flowing directly into Vietnam; of course, this information is secondary. Focusing just on Yunnan, the smallest branch of the Lancang River is the Snake River we seek. This river winds around a section of Mount Zhelong, flowing rapidly with a very steep drop. Some sections pass through underground tunnels or muddy swamps in the jungle, while others sharply descend along the mountain contours, resulting in one waterfall after another; the river is full of massive whirlpools, making passage impossible for any boat. Due to its extreme winding and twisting nature, it is called the Snake River. The local Bai people call it "Jielaluolan," meaning the evil dragon suppressed by the great snow-capped mountains.