Early the next day, Chen Yu arrived at the Xio base, where Daichi was already waiting at the entrance. Together, they entered a spacious laboratory provided by Dr. Fan Dorn, a scientist from Planet Fan Dorn.
"Let's take out the X device," Chen Yu suggested to Daichi, who nodded and placed the X device on the lab table.
"Please, help us out!" X gleamed on the device, addressing Chen Yu.
Without hesitation, Chen Yu retrieved his Spark Lance, placed it on his chest, and pressed the transformation button. Surrounded by light, he soon transformed into a human-sized Ultraman Tiga right before Daichi's eyes—a sight Daichi, despite his experience merging with X, had never witnessed before.
After nodding to Daichi, Chen Yu extended his hand, emitting his own light power. The seal on the X device began to fade under the glow until it completely disappeared.
"The seal's lifted!" X exclaimed from within the device.
"Thank you, Chen Yu!" Daichi, overjoyed, picked up the X device and expressed his gratitude.
Chen Yu nodded, then reverted to his human form. At that moment, the Blue Stone being researched by Dr. Fan Dorn in the lab started to shine.
Exiting the lab, they approached Dr. Fan Dorn to find the glowing Blue Stone. "Why is the Blue Stone glowing now when Gargorgon has already been dealt with?" Chen Yu wondered, puzzled.
Daichi and X were equally confused. X admitted ignorance about the stone's purpose, which was believed by Chen Yu to signal the advent of the original Ultraman.
Suddenly, Daichi's communicator buzzed with an urgent message from Xio: "A massive energy body is approaching Earth, set to arrive in thirteen minutes!"
Daichi, startled, rushed to the Xio hall, with Chen Yu following. Dr. Fan Dorn handed the glowing Blue Stone to Chen Yu, insisting, "This stone must have its use at this moment. Take it with you."
Knowing the severity of the situation, Chen Yu accepted the stone. He recalled the end of the Ultraman X movie, which hinted at a formidable monster named Dizastrous, though its true form was never shown.
As Chen Yu prepared to leave, he received a notification: [The mission world is changing... Nightmare difficulty identified! Stop Dizastrous from descending on Earth!]
Surprised by the sudden mission and increased difficulty, Chen Yu realized the true challenge was not Gargorgon but this unseen creature, Dizastrous.
Leaving the lab, Chen Yu saw Daichi merging with X, ready to confront the cosmic threat. "Why rush out?" he thought, realizing they were likely heading into a trap set by the space witch Mulnau, which would transport them to a different dimension.
Holding the Blue Stone, Chen Yu considered his options. Unable to transform into Tiga again due to energy depletion, he planned to use the Ultraman Leo transformation card, wondering if it would suffice against Dizastrous.
Suddenly, an idea struck him about another person who could transform into Tiga. Rushing to the Xio hall, he sought to involve Daichi's son, Yuto, realizing his crucial role in the upcoming battle.
Upon arrival, Chen Yu was informed by Captain Shin, "Daichi and X have already gone to face the monster."
"I'm here to help," Chen Yu replied, then asked, "Can you contact Professor Yuka Shiroyama?"
"Does she know about the monster?" Vice-Captain Tachibana asked.
"Not sure," Chen Yu answered, "but her son Yuto is essential to this fight."
The team was puzzled, unaware of how a young boy could play a significant role in the battle against a cosmic monster.