Li Ban could recognize the material of the hidden door so quickly only because Du An had recently shackled him with an Obscuring Sun Lock.
Obscuring Sun Locks suppressed the elements within a spirit practitioner's body, making it exceedingly difficult for them to use their abilities.
At the same time, they prevented their elements from absorbing new spiritual rhinoceros.
He didn't know why Sun-Obscuring Spirit Iron could suppress spirit practitioners, but he knew the material was incredibly expensive.
Because of that, even the Yu Province Death Prison reportedly had fewer than ten sets of Obscuring Sun Locks.
Yet the Hundred Flowers Pavilion actually used this material to build doors?
Weren't they a little too wealthy?
Li Ban gave the first hidden door a wide berth and continued forward.
Some ten meters later, he spotted a second hidden door.
He looked down at the silver hairpin resting in his palm.
"No wonder Lady Hua believed a single door could lock away a spirit practitioner. It turns out this door really isn't simple," he murmured.
Without breaking his stride, Li Ban arrived at a third hidden door.
Sure enough, the material was exactly the same.
With a dark room like this, they truly didn't have to worry about spirit practitioners breaking in to steal.
The heavy door was completely sealed, preventing Li Ban from seeing anything inside.
He found a small hole in the center of the door, perfectly matching the size of the hairpin.
Li Ban took a deep breath, gathered his focus, and swiftly slid the hairpin into the slot.
With a sharp click, the dark door slowly began to recede into the adjacent wall.
Not knowing exactly when Lady Hua's ten-breath time limit started, Li Ban didn't wait for the door to open fully. He turned sideways and squeezed himself through.
By the light spilling in from the corridor, he could see that the dark room was small—only about one zhang square.
The moment he stepped inside, Li Ban felt a wave of discomfort wash over him.
It just wasn't as intense as the suppression radiating from the door itself.
"It seems the surrounding walls are also mixed with Sun-Obscuring Spirit Iron, just not as heavily as the door," he thought.
His feet didn't stop moving as he pondered this, reaching the center of the room in just two steps.
A stone table sat there, bearing only a single book.
The cover read: Art of Awakening Life.
This was the payment the Cat Girl had asked Li Ban to retrieve for her.
Li Ban had no idea why the Cat Girl wanted this thing.
Art of Awakening Life was essentially the Hundred Flowers Pavilion's greatest trade secret.
It was the special method they used to cultivate tree-spirits.
Did the Cat Girl plan to wash her hands of her old life and make a living selling tree-spirits once she reached Yanzhou?
Li Ban snatched up the book and stuffed it into his shirt; in reality, he slipped it directly into his Cubic Heaven and Earth.
By this time, the heavy door had just fully recessed into the wall and hadn't yet begun to close. Li Ban hurriedly sprinted back toward the exit.
He didn't want to stay in this place for a second longer.
Li Ban practically bounded out of the dark room in a single leap, escaping before the door could seal him inside.
But the moment his feet hit the ground outside, before he could even let out a sigh of relief, the floor dropped out from under him.
A massive crack had abruptly split the corridor floor!
Li Ban furrowed his brow and instantly splayed out his arms and legs. He had only fallen half a meter before his limbs braced hard against the parallel walls, halting his descent.
Gathering his strength, he prepared to vault back up.
But the moment he looked up, a massive boulder plummeted straight toward his head with terrifying momentum, threatening to crush him into meat paste.
He frantically aborted his leap and released his grip on the walls.
Plummeting another two meters into the dark, he shot his arms and legs out once more, bracing himself against the narrow chute to catch his fall.
Right then, the boulder crashed down above him with a deafening boom, completely sealing the chasm. The violent tremor knocked Li Ban loose, sending him sliding another half a zhang down the shaft.
"The Hundred Flowers Pavilion is going back on their word?" Li Ban narrowed his eyes, his mind already racing for a way out.
Using both his arms and legs, Li Ban awkwardly shimmied his way down the vertical passage.
The air down here was thick with moisture, and the walls were so slick he nearly lost his grip several times.
After descending a fair distance, the shaft opened into a wider gap, and the rushing sound of water drifted up from below.
"There's an underground river with such fierce currents beneath the Hundred Flowers Pavilion?"
"Weren't they afraid the ground would cave in, building right over something like this?"
Then again, this wasn't a modern world of science and technology filled with towering skyscrapers. Perhaps the load-bearing limits of the earth were sufficient.
Because the walls were growing increasingly slippery, Li Ban simply summoned his element, the Iron-Eating Sword, using it as a makeshift climbing piton.
Clang!
The Iron-Eating Sword suddenly struck something rock-hard, sending a crisp vibration up his arm.
"That doesn't sound like stone," he realized.
Li Ban stopped his descent and groped around the surface with his free hand.
Suddenly, a thick iron plate swung down with a clatter, blocking off the rest of the vertical shaft and revealing a small tunnel branching off to the side.
"This trap can actually reroute and send intruders somewhere else?"
Li Ban immediately shifted directions and crawled into the newly revealed tunnel.
If the trap meant for him led straight down, he was more than happy to take an alternate route.
He soon found that this new passage slanted downward as well. After a short, sloping descent, it transitioned back into a sheer vertical drop. Carefully climbing down once more, he finally reached a wider clearing.
Instead of jumping down recklessly, he released the Silver Kingfisher, sending the little bird ahead to scout the way.
A moment later, the Silver Kingfisher fluttered back and leisurely perched on his shoulder.
"The Silver Kingfisher doesn't sense any danger. I should go down and take a look."
Still acting with extreme caution, Li Ban inverted himself in the shaft and slowly poked his head out the opening.
When he saw the scene below, his eyes widened in surprise.
Beneath him lay a massive cavern. Raging waters claimed one side of the cave, while a slightly elevated stone slope made up the other.
Woven vines formed a small flight of stairs leading up the slope's wall toward an arched exit.
Right where the slope met the water stood a heavy iron cage. Only its upper half breached the surface; the bottom half was entirely submerged in the river.
Several pale, luminescent stones lit up the cavern, casting their eerie glow over the figure trapped inside the cage.
It was the person in that cage who truly shocked Li Ban.
It was actually Yan Jiu, whom he hadn't seen in ages!
The dignified Ninth Imperial Princess and Master of the Assassin Hall was now a completely wretched sight.
She was still wearing the same servant's dress she had used as a disguise in the Myriad Ancient Pagoda. The fabric was torn in several places and stained with patches of dried blood.
The soaking wet dress clung tightly to her skin, deeply discolored by murky yellow water stains.
Who knew how long she had been soaking in there.
Before Yan Jiu could spot him, Li Ban yanked his head back into the tunnel.
"No matter what, Yan Jiu is a 6th Tier Spirit Cultivator, and she's fused with some incredibly powerful elements. How could she possibly be imprisoned here by the Hundred Flowers Pavilion, whose strongest experts are only 5th Tier Spirit Cultivators?"
"Could the joint operation between the Assassin Hall and the Hundred Flowers City Lord actually be a rescue mission for Yan Jiu?"
The Hundred Flowers Pavilion was definitely far more complex than it appeared on the surface.
If they could lock away someone like Yan Jiu, they had to have other methods hidden up their sleeves.
But right now, Li Ban had no other way to escape.
The arched opening on the sloped wall below seemed to be the only exit out of these hidden passages.
If he went over there, he was bound to draw Yan Jiu's attention.
There weren't any large, connecting shadows down here either, meaning he couldn't use his Shadow Meld ability.
Would he have to rely on the Invisibility Plain Ring?
But wasting the Plain Ring's final use just to sneak past an imprisoned Yan Jiu felt like a massive waste.
Li Ban's current tunnel opened right into the cavern's ceiling, and there was absolutely nowhere else for him to climb or transfer to.
The trap was explicitly designed to dump whoever fell into it straight into the subterranean river.
In the end, he had the Silver Kingfisher dive into the water first to scout. Once he confirmed there were no obvious threats lurking beneath the surface, he gritted his teeth, let go of the walls, and plunged into the river.
The heavy splash naturally caught Yan Jiu's attention.
She had been gripping the upper bars of the cage, resting her head on her arms while letting the water's buoyancy support her weight.
Now, she jerked her head up, straightened her body, and peered toward the churning water.
A second later, Li Ban surfaced near the rocky slope.
He kept himself several chi away from the iron cage.
He was still on guard against her.
When Yan Jiu recognized his face, her eyes went wide with shock. She pressed her face against the iron bars, mouth agape. "Li Ban? What are you doing here?"
Li Ban wiped the river water from his face as he waded up the slope. "Isn't Hall Master Yan here as well?"
Even as he answered her, he didn't stop moving, eager to escape through the arched exit above as fast as he could.
Yan Jiu desperately pressed harder against the bars, anxiety lacing her voice. "Li Ban, don't leave! Can you get me out of here? I can pay you a lot of money and rare elements!"
"My apologies, Hall Master Yan. That cage of yours is forged from Sun-Obscuring Spirit Iron. I can't break it open," he replied.
By the time he finished speaking, he was already nearing the arched exit.
"You can't get out through that tunnel!" she cried. "I know the way out. Just find a way to help me, and I'll guide you through the underwater route!"
Li Ban halted in his tracks. Using his body to shield the movement, he stealthily released the Silver Kingfisher from his hand.
With the Silver Kingfisher around, he naturally wouldn't blindly walk into a tunnel rife with blind spots.
But judging by Yan Jiu's words, she seemed to know something about this place.
While he waited for the bird to scout ahead, Li Ban decided to chat with her.
"Since Hall Master Yan understands this place so well, how did you end up locked in a cage? Was the Hundred Flowers Pavilion originally your property?"
Given that Yan Jiu was now imprisoned in a cage made of Sun-Obscuring Spirit Iron, the pavilion had obviously fallen into someone else's hands.
Yan Jiu let out a soft sigh.
She knew that if she couldn't offer any genuinely useful information, Li Ban would simply turn around and walk away. He wouldn't lift a finger to save a former enemy.
Though, truth be told, they could still be considered enemies even now.
"After fleeing the Myriad Ancient Pagoda, I was hunted down by a Priest and severely wounded," she began. "If I hadn't been protected by my dragon qi, I wouldn't have survived."
"Once I temporarily shook off my pursuers, I disguised my appearance and hid in the Hundred Flowers Pavilion. But who could have guessed they would see right through me? They locked me in this water dungeon. I broke out several times, but they caught me every time. And now, they've locked me in this cage of Sun-Obscuring Spirit Iron."
Yan Jiu looked up, her fingers tracing the cold iron bars in front of her. "They have a massive hoard of Sun-Obscuring Spirit Iron here. This place is absolutely not simple. If you rush blindly down that tunnel, you'll probably trigger another Sun-Obscuring Spirit Iron trap, and then you truly won't be able to escape."
"The underwater route is the only way to avoid the vast majority of their traps. I have a merfolk bloodline, which allows me to breathe underwater. You wouldn't even need to expend any stamina; you'd just have to hold your breath for about fifteen minutes. I swim extremely fast. I can definitely guide you out of this underground river."
Right then, the Silver Kingfisher fluttered back into Li Ban's palm.
Li Ban offered a faint smile. "My apologies, Hall Master."
If he wanted to rescue Yan Jiu, he would first have to find a way to open the cage.
Under these circumstances, expecting him to go hunt down the key or find a tool strong enough to force the bars apart was a complete joke.
Li Ban stood at the very top of the vine stairs.
The Silver Kingfisher had already scouted ahead, confirming that there was no one currently lying in ambush within the passage.
However, the traps Yan Jiu mentioned were indeed a problem.
He could usually find ways to dodge or break ordinary traps, but if he stumbled into another one made of Sun-Obscuring Spirit Iron, things would get incredibly troublesome.
He thought back to what Yan Jiu had just said about swimming out through the underground river.
Yan Jiu had a merfolk bloodline, meaning she could swim underwater for extended periods without ever needing to surface for air.
Li Ban also possessed an element: Sea Bream Gills.
It was an element he rarely used, but when he did, it was a genuinely life-saving ability.
Having advanced to the 3rd Tier, his Sea Bream Gills now allowed him to breathe underwater for up to a full day.
Even if Li Ban was completely unfamiliar with these waterways, he didn't have to worry about getting lost in the depths.
With an entire day at his disposal, he would eventually find an exit—or dig one out himself.
Yet just as Li Ban prepared to jump off the stairs and dive back into the water, the woven vine steps beneath his feet abruptly shifted. Snaking out like the tentacles of an octopus, the vines lashed up and firmly wrapped around his ankle.