Following the system's directions, Su Yao headed towards the source of the mysterious energy fluctuations. After leaving the underground warehouse, the extreme cold outside intensified. Every step felt like a battle against an invisible enemy, the chill constantly eroding her body. Even with her protective gear, she could feel the cold seeping into her bones.

Along the way, Su Yao saw that the buildings on both sides of the street were covered with thick layers of ice, resembling giant ice sculptures. Some buildings, unable to bear the weight of the ice and snow, had begun to collapse, emitting dull thuds that echoed through the silent streets, adding to the desolation and terror of the apocalypse.

As she approached the source of the energy fluctuations, the surrounding environment became increasingly eerie. A thin layer of blue mist permeated the air, and when this mist touched Su Yao's body, it felt as if her soul was frozen. Su Yao was startled; she realized the danger here was far greater than she had imagined, and thus she proceeded with even greater caution.

After turning a street corner, Su Yao saw a building shrouded in a massive block of ice. The building emanated intense energy fluctuations, the mysterious energy seemingly emanating from within. The building's entrance was blocked by a huge ice boulder, covered in strange runes that shimmered with a chilling light, as if warning anyone who came near.

Su Yao tried to melt the ice with her supernatural abilities, but she found that her fire power was severely suppressed here. The flames were extinguished by a powerful, cold force the moment they touched the ice. Su Yao frowned and began searching the surrounding area for other ways to enter the building.

On one side of the building, she found a ventilation shaft. It was partially blocked by ice and snow, but still passable. Su Yao carefully climbed into the shaft; it was narrow and cold inside, the walls covered in ice spikes. She struggled forward, her clothes torn by the ice spikes, leaving her with several cuts, but she persevered.

As she entered the building through the ventilation shaft, she was stunned by what she saw. The interior was a vast space with an ice pillar emitting a deep blue light at its center. A blurry figure seemed to be sealed within the ice pillar, surrounded by countless energy chains that connected to various corners of the building, forming a complex energy array.

Su Yao sensed that this ice pillar was the source of the extreme cold. The mysterious energy fluctuations were emanating from the ice pillar, and she could detect that the power within it was gradually increasing. If it wasn't stopped, the extreme cold would worsen, and the entire world would be covered in ice and snow.

Just as Su Yao was about to approach the ice pillar for further observation, a group of ice-blue ghosts suddenly surged out of the surrounding shadows. These ghosts were of various shapes, some humanoid, some animaloid, their bodies transparent as ice, radiating a bone-chilling cold. The ghosts pounced on Su Yao, and wherever they went, the temperature plummeted, and the air around Su Yao began to freeze.

Su Yao hurriedly used her supernatural ability, attempting to attack the ghosts with fireballs. However, the fireballs only momentarily paused the ghosts upon contact, without causing any real damage. The ghosts continued to charge towards Su Yao, extending their icy claws in an attempt to grab her.

Su Yao began dodging the ghosts' attacks inside the building, using the surrounding obstacles to maneuver around them. While dodging, she discovered that the ghosts seemed particularly sensitive to light. So, she retrieved some flares from her storage space and threw them at the horde of ghosts. The intense light from the exploding flares temporarily dispersed the ghosts, preventing them from approaching.

Taking advantage of the opportunity, Su Yao walked towards the ice pillar again. As she approached, she could feel the chilling power emanating from it almost freezing her body. Her special ability seemed extremely weak in the face of such powerful cold, but she did not give up.

Su Yao carefully observed the ice pillar and noticed some similarities between the runes on it and those on the surrounding ice and stones. She guessed that these runes might be the key to unlocking or destroying the energy array. Therefore, she began to try to decipher the runes, hoping to find a way to stop the ice pillar from releasing its power.

While studying the runes, Su Yao discovered that they seemed to be an ancient language, and she had seen similar symbols in the ancient books she had collected before. She tried hard to recall the contents of the ancient books, attempting to find the meaning of the runes. After some effort, she finally deciphered part of the runes' meaning. These runes mentioned an "Extreme Cold Core," and only by finding and destroying it could the energy release of the ice pillars be stopped.

However, the runes didn't provide a clear clue as to the location of the "Core of Extreme Cold." Su Yao continued searching for clues around the ice pillar and discovered a small energy reaction device at its base. This device was connected to the energy chains within the ice pillar and was also covered in runes. Su Yao guessed that the "Core of Extreme Cold" might be inside this device.

Just as she was about to operate the device, the ghosts swarmed around her again. This time, the ghosts seemed even more ferocious, charging towards Su Yao relentlessly. Su Yao was in a life-or-death crisis; she had to find the "Core of Extreme Cold" and destroy it as soon as possible, otherwise not only would her own life be in danger, but the entire world would be swallowed up by this endless extreme cold.