Following the sound, the wall revealed a secret passage leading into a bottomless abyss. Dust swirled with faint light, carrying a pungent, musty odor.
Sheng Chenjin, without a word, shielded the person beside him and moved aside.
The secret passage seemed ancient. With the dim light from outside the window, Shi Xinxin could barely make out the muddy path within, strewn with protruding stones.
Shi Xinxin took out her flashlight and cautiously shone it into the seemingly bottomless passage. All she saw were cobwebs coating the walls and a thick layer of dust.
She glanced at Sheng Chenjin. It seemed that just scouting the area above was not enough; they had to go down.
Shi Xinxin had come here prepared for the worst. She exhaled softly, a sense of urgency now dominating her thoughts.
She didn't notice the unusual expression on Yan Hao's face.
Looking at the familiar path before him, a memory seemed to resurface, and Yan Hao clenched his fists tightly.
"Why don't we go down and take a look? If you're worried, I can go down first to scout the way and call you once I confirm it's safe." Shi Xinxin looked ahead, the beam of her flashlight probing deeper into the passage. This time, she could see the end of the dilapidated path, a dark, cavernous opening.
Sheng Chenjin clasped her hand in return, his broad palm enveloping her small one.
He stepped into the passage first, surveying his surroundings as he spoke, "Having a girl go on an adventure is not my style, especially when you are the one I care about."
A hint of amusement colored his tone. Shi Xinxin's face flushed involuntarily, knowing he was trying to break the tense atmosphere. She said nothing.
She turned. "Senior brother, you..."
Yan Hao had by then regained his composure. He looked at them, smiling gently, "This secret passage holds no difficulty for me. Besides, as your senior brother, I should protect you."
Sheng Chenjin tightened his grip on Shi Xinxin's hand subtly.
Sensing the increased pressure on her hand, Shi Xinxin tugged at the corner of her lips. "Alright."
Thus, Sheng Chenjin took the lead, holding Shi Xinxin’s hand tightly as if afraid she might disappear. Yan Hao followed behind them.
As he saw the familiar scenery before him, Yan Hao's expression grew increasingly grim.
The secret passage was likely only wide enough for an adult, about 1.8 meters tall. Sheng Chenjin had to bend slightly as he walked forward.
Entering the passage, Shi Xinxin watched her footing on the stones and periodically glanced at the walls, her gaze sweeping over the dust-laden surfaces.
She tugged Sheng Chenjin's hand. "There's no danger here, nor any clues. Hurry up."
"Don't worry, if there's danger, I'll be the one in front of you," Sheng Chenjin replied, striding forward, his narrow eyes casually scanning the terrain.
Although the tunnel appeared long from above, it was only about ten meters long in reality. Shi Xinxin and her companions stopped at the so-called "black hole."
Shi Xinxin shone her phone directly ahead. This was not a black hole like the one she had seen from above, but a locked iron door.
Shi Xinxin then focused on the lock on the iron door. The flashlight beam shone directly on the lock, and Shi Xinxin could clearly see the intricate patterns on it, which suddenly seemed familiar.
Her eyes lit up. She took a hairpin from her hair and handed it to Sheng Chenjin. "This lock is the same as the one on the pharmacy door."
Without needing further explanation, Sheng Chenjin understood her intention. He took the hairpin, his skilled hands...
Unexpectedly, the journey had been so smooth. Shi Xinxin breathed a sigh of relief. Though a sense of unease lingered, the current emergency left her no room for extensive thought.
She instinctively glanced at Yan Hao, who stood behind them. In the light of the nearby flashlight, she could see beads of cold sweat on his forehead. Shi Xinxin frowned. "Senior brother, are you feeling unwell? Why are you sweating so much?"
She quickly added, "If you don't feel well, you should go up to rest. We'll be fine here."
Meeting her anxious gaze, Yan Hao smiled and shook his head. "I'm fine. It might be a bit hot underground. I'll be better in a while."
By this time, Sheng Chenjin had already picked the iron lock. He casually tossed the rusty lock aside and then looked over.
"If you're not feeling well, don't push yourself. Don't end up dying here with no one to clean up," he said, unusually looking at Yan Hao for a few extra moments.
Shi Xinxin playfully pinched his arm. "Can't you say something nice? Why are you saying such disheartening things in a place like this!"
Sheng Chenjin finally fell silent, albeit with a hint of helplessness.
Hearing Yan Hao insist he was fine, Shi Xinxin reluctantly accepted his assurance, allowing him to continue following them.
"If you feel unwell later, you must tell us immediately," Shi Xinxin said, turning back to remind him once more, her concern evident.
Yan Hao's face showed no sign of discomfort. Seeing Shi Xinxin's determined concern, he smiled slightly and nodded in agreement. "I know. Now you're the one looking after your senior brother."
Thinking of her current stern demeanor, so reminiscent of how he used to discipline her, Shi Xinxin pursed her lips slightly.
Sheng Chenjin spoke up. "I've already picked the lock. Are we going or not?"
"Let's go, let's go," Shi Xinxin said, giving him a good-natured glare, and was then ushered forward by him, following behind.
As the iron door opened, revealing the scene within, Shi Xinxin's emotions shifted instantly.
The interior was a stark contrast to the dilapidated state of the exterior. Faced with advanced research machinery, and a whole wall of experimental drugs and findings, Shi Xinxin's hands, hanging at her sides, clenched slightly.
She knew these substances were unlikely to be benign. They were probably just another step in Old Feng's mad plan.
Yan Hao's lips thinned, and he looked at the familiar room with a blank expression.
Sheng Chenjin's gaze swept over the various items, finally resting on something next to the wall of experimental drugs.
It was an iron door, entirely out of place in this research facility.
Shi Xinxin clearly noticed this door as well. They exchanged a look and nodded at each other.
Receiving affirmation in their shared glance, Sheng Chenjin slowly approached the iron door.
Hearing no sound from within the iron door, Sheng Chenjin's expression changed, and he kicked it open.
Seeing the rapid shift in his face, Shi Xinxin looked over with bated breath.
It was empty!
"Damn it, he still managed to escape!" Shi Xinxin deflated like a balloon, her hands clenched.
They had arrived as quickly as possible, yet Old Feng had still managed to get away. It felt as if all their hopes had been placed on something, only for it to shatter instantly.