A soldier with a jetpack stumbled out from within.
He had just reached the doorway, looking left and right.
Though he appeared carefree, he couldn't shake the feeling that something was off today.
He sniffed the air, noticing an inexplicable fragrance lingering in the atmosphere—a scent reminiscent of citrus blossoms.
It had been a long time since he had smelled such a fragrance in the stifling underground space.
With a suspicious gaze, he looked at the door he had just opened, behind which lay a shadowy expanse.
Just as he took a step toward the shadows, a human soldier patrolling below shouted up to him.
"Old Yang, catch!"
A fluorescent substance, similar to some kind of drug, flew through the air toward him. The soldier known as Old Yang halted his step toward the door and turned to catch the substance.
Meanwhile, behind the door, in the shadows, Ning Yu's Blood Kite was already poised to strike.
After catching the substance, Old Yang seemed to have a new objective. He leapt from above, activating his jetpack.
He descended slowly, heading toward the group of soldiers whispering among themselves, intending to say something.
At the same time, three figures had already vanished from the shadows behind the door, slipping into the depths beyond the mechanical gate.
The interior space was far more intricate than the outside. All the passageways were constructed from some kind of high-strength metal.
The metal walls were adorned with complex yet aesthetically pleasing patterns, composed of straight and diagonal lines that gave off a futuristic vibe.
However, these patterns seemed to serve more than just a decorative purpose. White energy flowed through them in waves, following some kind of rhythm.
Ning Xuan led the way, with Ning Yu and Shen Yiyue following closely behind. For now, the passage was empty.
"Hiss..."
Almost as soon as they entered, Ning Xuan suddenly clutched her head, as if in pain.
"Xiao Xuan, what's wrong?"
Ning Yu stepped forward, concern in her eyes as she studied Ning Xuan's expression and movements.
"It's nothing, sister. I might just be exhausted from these past few days."
For a brief moment, Ning Xuan's eyes seemed to flicker with some kind of signal, patterns flashing across them before disappearing just as quickly.
She quickly composed herself, standing straight again. Ning Yu watched her from behind, her gaze thoughtful and contemplative.
As the three of them approached a corner, they suddenly heard the sound of footsteps.
Ning Xuan's hand had already transformed into a metallic blade, but Ning Yu stopped her.
Soon, a group of patrolling soldiers walked by. They didn't turn in their direction, as this path led toward the exit.
The soldiers glanced toward the door before continuing on their way.
The three of them clung to the ceiling, completely silent.
After descending, they arrived at a checkpoint—a small room with metal panels inside.
At the moment, there were no soldiers stationed there.
"Sister, I'll see if I can retrieve a map of this area."
Ning Xuan informed Ning Yu before stepping inside. On the underground engineering map she had provided, this area was marked, but the details were absent.
Ning Yu nodded lightly, waiting outside with Shen Yiyue.
Once Ning Xuan was inside the checkpoint, Ning Yu leaned over and whispered to Shen Yiyue:
"How do you feel?"
"Something's off."
Shen Yiyue didn't look at Ning Xuan, who was busy operating the panels inside. Instead, she pretended to be casually chatting with Ning Yu.
"Should we make a move, Xiao Yu?"
Ning Yu shook her head almost imperceptibly. Shen Yiyue blinked in understanding. Just then, Ning Xuan emerged from the checkpoint.
"Sister, I've retrieved the data."
She raised her arm, displaying a holographic map of the ritual's core area.
The entire structure, though underground, was designed in a spiraling downward pattern. Two passageways intertwined, leading deeper into the earth.
At the very bottom, the two spiral passageways converged at a central point.
From above, the area resembled two intertwined yin-yang fish, merging into one.
This central point was undoubtedly the core of the ritual—the very destination the trio sought.
"We can take this path."
Ning Xuan pointed to a small route that led directly to the entrance of the double-spiral passageway.
"The checkpoint guards are minimal here. It seems to be the same route that soldier used earlier."
Ning Yu studied the map carefully. Green circles marked the locations of the guards and their patrol routes at different times.
She glanced up at Ning Xuan, whose expression was unreadable. Her lake-blue eyes were calm, yet deep and unfathomable.
Everything felt too coincidental.
They had just entered, and already they had found an unguarded checkpoint and a direct path to their target.
It was as if everything had been prepared, waiting for Ning Yu to walk into the trap.
But Ning Yu wasn't one to retreat. Though Ning Xuan showed no hostility, Ning Yu knew that this might not entirely be Ning Xuan's own will.
They followed the planned route, bypassing all the guards. Occasionally, they encountered soldiers slacking off during their shifts.
These unfortunate souls were swiftly dealt with by Ning Xuan's blade, their bodies stuffed into trash bins without a sound.
As they ventured deeper, the atmosphere grew increasingly oppressive. An invisible pressure weighed on the air, accompanied by a faint, buzzing white noise.
Living in such an environment for long would likely drive an ordinary person to the brink of a nervous breakdown.
The patterns on the metal walls grew denser, pulsing like a living thing—brightening and dimming in an irregular rhythm.
The spiral-shaped underground structure seemed alive, breathing slowly and steadily.
After navigating through winding passageways, they finally stood before the double-spiral passage.
A small area lay before them, marked by two small doors—one black, one white.
Ning Yu and her companions stood on the higher ground, while the two doors below were slightly ajar, as if inviting them in.
The three exchanged glances, about to discuss their next move, when suddenly, the space around them began to tremble violently, as if struck by an earthquake.
The area behind them collapsed with a deafening roar, accompanied by the distant screams of soldiers.
Something had been activated.