Su Yao and Ling Yu arrived at the gate of the mountain fortress, only to find it tightly shut, covered in mysterious runes that exuded an ancient and enigmatic aura against the backdrop of ice and snow. Su Yao attempted to use the system to unlock the gate, but the system indicated that a specific energy source was needed to activate the runes.

They began searching around the gate. Ling Yu noticed something unusual about the nearby snowdrifts. He used his ice-based abilities to move the snowdrifts aside, revealing a hidden basement entrance. The two cautiously entered the basement, which was filled with an old, worn atmosphere. Ancient weapons and maps hung on the walls.

At the far end of the basement stood a stone platform, upon which rested a crystal emitting a ghostly blue light. The crystal's energy fluctuations resonated with the runes on the door. Just as Su Yao was about to pick up the crystal, the basement suddenly trembled violently, and cracks began to appear in the surrounding walls. From these cracks crawled several ice spiders, their bodies radiating fluorescence.

These ice spiders were enormous, their legs like sharp ice blades, and they swiftly crawled towards Su Yao and Ling Yu. Su Yao activated her spatial wind blades, repelling the approaching ice spiders, but more ice spiders swarmed in from all directions. Ling Yu, on the other hand, created ice walls around them, attempting to block the ice spiders' attack.

However, the silk spun by the ice spiders was highly sticky and corrosive, quickly corroding large holes in the ice wall. Su Yao seized the opportunity, teleported to the edge of the stone platform, and picked up the crystal. The instant she picked it up, a beam of light shot out from it, blasting away all the surrounding ice spiders.

The two hurriedly left the basement and returned to the main gate. Su Yao placed the crystal into a groove on the gate, and the runes began to flash, causing the gate to slowly open. Upon entering the mountain fortress, they found it eerily silent, with thick snow covering most of the area, and some buildings in ruins.

Su Yao's system notification indicated a large amount of supplies in the central area of ​​the fortress. They headed towards the center, passing through a plaza with many statues frozen in ice and snow. These statues were of various shapes and sizes, some depicting warriors and others civilians, as if telling the story of this place before the apocalypse.

As they approached the central area, they encountered a group of mechanical puppets blocking their way. These puppets, armed with weapons and with red glowing eyes, immediately attacked upon spotting Su Yao and Ling Yu. Ling Yu used his ice-based abilities to create an ice shield, deflecting the puppets' fire, while Su Yao used her spatial abilities to teleport some of the puppets into a distant building.

However, the sheer number of mechanical puppets overwhelmed them, and they gradually found themselves in a difficult battle. During the fight, Su Yao discovered that there seemed to be some kind of signal connection between the puppets. She focused her mind and used her system to interfere with these signals. Under her interference, the actions of some of the puppets became chaotic.

Taking advantage of the opportunity, Ling Yu activated his ice-based ability, condensing the surrounding water vapor into giant ice spikes, which he fired at the puppet horde. The ice spikes pierced through the bodies of some puppets, rendering them immobile. Su Yao continued to intensify her interference with the puppets' signals, while simultaneously activating her wind blade ability to attack those puppets that were still moving.

After a fierce battle, they finally defeated the mechanical golems and reached the central supply warehouse. The warehouse door was protected by an energy shield, and Su Yao's system began analyzing how to break through it. During the analysis, the temperature around the warehouse plummeted, and frost began to spread across their bodies.

Su Yao realized this was the warehouse's defense mechanism at work, and she and Ling Yu had to break through the shield as soon as possible. With the system's help, they finally found the shield's weakness. Su Yao combined her spatial and fire abilities to attack the weak point. Cracks appeared in the shield under the attack, and Ling Yu used his ice abilities to further widen the cracks, ultimately successfully breaking through the shield.

Upon entering the warehouse, they were stunned by what they saw. The warehouse was overflowing with all sorts of supplies: large quantities of food, medical supplies, weapons and ammunition, and even some high-tech equipment. Su Yao excitedly began using her spatial storage to store these supplies. These supplies were enough for them to survive in the apocalypse for a long time, and with these resources, they could better help other survivors.

During their resource gathering, Su Yao's system detected a hidden chamber containing a mysterious control panel. The panel displayed information about the causes of the apocalypse and possible solutions. Su Yao and Ling Yu realized this could be key to changing the entire post-apocalyptic situation. They decided to take the information, leave the mountain fortress, and search for more survivors to work together to change the world.