After successfully upgrading the safe house, Su Yao and her team enjoyed a relatively peaceful period. Su Yao continued to practice her abilities daily and explore more functions of the system, while her team members honed their skills, always ready to face the next crisis.

That day, Su Yao was studying some mysterious crystal cluster samples she had collected during her previous adventures when suddenly, the container holding the crystal clusters began to vibrate violently and emit a dazzling light. Su Yao was startled; she had never seen these crystal clusters behave so strangely before.

"System, detect the cause of the crystal cluster anomaly!" Su Yao hurriedly issued the command in her mind.

The system responded quickly: "An unknown high-temperature energy wave has been detected converging on this location. This energy wave resonates with the crystal cluster and may cause the crystal cluster's energy to go out of control."

Su Yao knew that if the energy of the crystal cluster got out of control, it would not only cause huge damage to the safe house, but could even affect the entire area. She immediately gathered her team members and said with a solemn expression, "Everyone, prepare for battle. This crisis may come from the explosion of energy inside the crystal cluster. We must find a way to stabilize it."

The team members nodded in agreement and used their special abilities to protect the safe house layer by layer. Su Yao, on the other hand, focused her attention on trying to establish a mental connection with the crystal cluster to find the root cause of the energy out of control.

As the unknown high-temperature energy wave approached, the crystal cluster vibrated more and more intensely. Large beads of sweat appeared on Su Yao's forehead. Her mental energy, like a small boat in a storm, struggled to navigate the chaotic fluctuations of the crystal cluster's energy. Finally, she discovered the problem. It turned out that this high-temperature energy wave contained a special frequency that resonated with the energy structure inside the crystal cluster, causing it to frantically absorb energy and teeter on the brink of losing control.

“I need your help to build a stable energy field so I can adjust the frequency of the crystal cluster,” Su Yao shouted to her team members.

The team members acted swiftly. The Earth Elementalist built a sturdy earthen embankment around Su Yao, the Wind Elementalist created a vortex of airflow above, and the Fire and Water Elementalists released opposing energy flows around Su Yao, which intertwined to form a preliminary energy stabilization field.

Su Yao took a deep breath and slowly reached her hands towards the crystal cluster. She activated her special ability, carefully injecting it into the crystal cluster, attempting to change the frequency of its internal energy. However, the interference from the high-temperature energy wave was extremely strong, making each step forward incredibly difficult for Su Yao.

"Hold on, Su Yao!" The team members shouted encouragement from the sidelines, while continuously increasing the intensity of the energy stabilization field.

In the fierce struggle against the high-temperature energy waves and the crystal cluster energy, Su Yao suddenly had a flash of inspiration. She remembered a method of energy harmonization that she had seen in ancient texts. So, she changed her strategy, no longer forcibly suppressing the energy of the crystal cluster, but instead guiding the high-temperature energy waves and the crystal cluster energy to merge with each other, bringing them to a new state of equilibrium.

Su Yao's hands moved faster and faster as she chanted incantations. The light from the crystal cluster gradually changed from chaotic to orderly, and the vibrations slowly subsided. Finally, through Su Yao's tireless efforts, the crystal cluster was successfully stabilized, and the unknown high-temperature energy wave was absorbed and transformed, merging into the crystal cluster and making its contained energy even more powerful.

Su Yao slumped wearily to the ground, but a relieved smile appeared on her face. "Although this crisis has been averted, it has served as a wake-up call for us. Our understanding of crystal clusters is far from sufficient, and we must continue to conduct in-depth research."

In the days that followed, Su Yao devoted more of her energy to the research of crystal clusters. Through systematic simulation of various energy environments, she conducted repeated experiments on crystal clusters, gradually mastering more of their characteristics and application methods.

At the same time, Su Yao realized that relying solely on the safe house's defenses was insufficient. They needed to take the initiative, explore the source of the high-temperature apocalypse, and find a way to completely resolve the crisis. Therefore, she began to formulate a series of exploration plans, preparing to lead her team out of the safe house at the appropriate time, venturing into unknown and dangerous areas, bravely moving forward to protect their families and the last hope in this post-apocalyptic world.