Was there a necessary connection between Huiyuan, who had died thirteen years ago, and the main hall that had been built thirteen years ago?

“Master, do you know which donor funded the construction of this main hall?”

The nun answered, “This poor nun does not know. That matter was handled by Abbess Huian and Master Huixiu.”

The matter seemed once again to circle back to those two people, Huian and Huixiu.

Shi Ting glanced at the magnificent main hall, lost in thought.

After the two of them left the Zangguan Hall, they made their way to the courtyard where Huiyuan had once lived. Shi Ting had already visited this place twice, though he had found nothing particularly unusual.

The courtyard had a row of main rooms, with two side chambers flanking them. On the surface, it appeared to be an ordinary, unremarkable little courtyard.

Shi Ting inspected every room in turn and found no mechanism of any kind.

He moved back and forth between the rooms and the courtyard, going in and out repeatedly. Yan Qing knew he was searching for a hidden mechanism, but she had no knowledge of such things and could only stand to the side, unable to help.

“Yan Qing, find me a ruler.” Shi Ting had first paced out the distances with his steps, but then felt this was not precise enough.

Yan Qing hurried to ask one of the nuns in the temple for a long wooden ruler.

Shi Ting took the wooden ruler and walked back and forth between the two side chambers. Finally, his gaze fixed on the south-facing side chamber.

“Have you found something?” Yan Qing saw a flash of excitement in his eyes.

Shi Ting said, “Both the north and south side chambers are attached to the main room, so in principle, the two side chambers should be exactly the same size. Yet the south chamber is sixty centimeters wider than the north one.”

Yan Qing looked from a distance; with the naked eye, it was indeed very difficult to detect that sixty-centimeter difference.

“When I measured from outside the side chambers, the south one is sixty centimeters longer than the north. But when I measured from inside, both chambers are exactly the same length and width.”

Yan Qing immediately thought of something. “Then the extra sixty centimeters is hidden inside?”

“Correct.” Shi Ting said with confidence. “That extra sixty centimeters on the outside is concealed within this side chamber. That space is just large enough for a staircase, enough for one person to pass through.”

Shi Ting entered the south side chamber. Piles of miscellaneous objects cluttered the space, and the walls were mottled with age.

“Shi Ting, look—there’s a bagua disk here.” Yan Qing tried to move it, but the bagua disk did not budge at all; it was embedded into the table.

Shi Ting walked over and noticed that everything around the bagua disk was covered in dust, while the disk itself was completely clean.

“So the mechanism is this.”

“But what does it mean? Do we need to solve the hexagram?” Yan Qing felt her head spin at the prospect. She had studied so many things in school but had never studied feng shui or the bagua. Though there was someone at the bureau who understood such things and it was often used in solving cases.

The mystical arts of the I Ching were an immense field of study, one that many people devoted their entire lives to.

“Rotating the hexagram positions to the correct alignment should open the hidden door.”

Yan Qing looked at him with anticipation. “Shi Ting, do you understand the bagua?”

Shi Ting handed the ruler to Yan Qing. “I only know the basics. I hope the hexagram configuration here is not too difficult.”

He gently rotated the disk as he explained: “Heaven above and heaven below forms the Qian hexagram, and Qian corresponds to the Open Gate. If we take it by sound association, as long as I turn to the Qian hexagram, a door should open.”

“And if that’s wrong?”

“If wrong, there’s still the Life Gate, but I think the Open Gate is the more likely option.”

Shi Ting turned the bagua disk to the corresponding position. In the tense anticipation of both of them, a faint sound reached their ears, and then one side of the wall slowly swung open, revealing a pitch-dark space within.

Both of them were overjoyed.

“You were right.” Yan Qing could not help but plant a kiss on his cheek. “Worthy of being my husband—truly omniscient.”

Shi Ting laughed. “I was only guessing. Just lucky.”

He took out his flashlight and shone it into the narrow space. “This distance exactly corresponds to the extra measurement outside—there is a hidden space concealed within.”

It was a downward staircase, steep and narrow, able to accommodate only one person at a time.

Shi Ting led the way with the flashlight, while Yan Qing gripped his arm tightly and followed close behind.

The staircase extended a full seven or eight meters down into the earth.

Only when they reached the bottom did the space open up before them. To Yan Qing’s astonishment, the underground passages branched into numerous tunnels, dark openings everywhere, like a subterranean honeycomb.

The two followed one of the passages and walked on, only to discover a faint glimmer of light not far ahead.

Light meant signs of life. Someone truly lived in this damp underground space.

They moved as quietly as possible, and the distant light drew ever closer.

Shi Ting shielded Yan Qing behind him. They advanced until they reached the source of the light, but to their surprise, no one appeared along the way.

The light came from a kerosene lamp. Against the rock wall stood a bed, the bedding neatly folded. Under the bed were two boxes, and atop the boxes lay some everyday objects.

Among these everyday objects, Yan Qing discovered a sachet that looked very much like the ones belonging to Huixiu and Huian.

“It seems the occupant is not here.” Yan Qing said softly. “This tunnel must connect to other places as well.”

“More than one place.” Shi Ting swept the flashlight around and found several more passages. “This tunnel is very old. It must be over a hundred years since it was built.”

“That long?” Yan Qing was startled.

“Although I don’t know what it was originally used for, whoever built Baiyun Nunnery must have discovered it and made that side chamber its entrance.”

“I wonder whether Huian knows about this.”

“If she knew, she could have figured out how Huixiu ended up hanging in the waterfall. But this place has not been sealed off, which means she doesn’t know.” Shi Ting took Yan Qing’s hand and felt their way forward. “My guess is that when Huiyuan was living in that courtyard, she happened to discover the secret of the bagua disk, and from that moment she knew this secret passage existed.”

“With so many exits in this tunnel, I wonder which one leads to the waterfall?”

“Let’s look around.” Shi Ting said.

The two took the flashlight and carefully explored the underground passages. They did not know how long they walked before another point of light appeared ahead. When they reached the source of that light, Shi Ting couldn’t help but furrow his brow.

For it was the very same kerosene lamp they had seen before, the same bed and boxes, identical in every detail.

“We’ve come back to the starting point.” Yan Qing was equally astonished. “I remember we entered from that opening—how have we ended up back here?”

“It seems this underground passage is also a bagua maze.” Shi Ting pointed the flashlight toward several exits. “With this place as the center, there are eight exits in total. As the saying goes, the great ultimate gives rise to two forces, two forces give rise to four forms, four forms give rise to eight trigrams, and eight trigrams generate sixty-four lines. Within these eight exits are further branches, intricate and endlessly varied. If one charges through without a method, one will only keep returning to the starting point.”

“Then let’s wait here for its owner to return. His bed is here—he surely won’t stay away forever, will he?”

“If he discovers that someone has broken into the passages, he will never come back. He will leave us to fend for ourselves here.”

Shi Ting pointed the flashlight back the way they had come. “And we cannot go back either—the tunnel we came through has already disappeared.”

Only then did Yan Qing notice that the path they had taken earlier had somehow shifted.

“The person who built this passage was a genius. Its design is perfectly suited for hiding. Even if someone finds this place, they will absolutely never find the person concealed within. On the contrary, not only will they fail to find the person they seek—they themselves will be trapped, and with no water or food, within a few days they would starve and die of thirst.”

“Shi Ting, can you find a way out?”

Shi Ting shook his head. “I only have a rudimentary understanding of bagua mazes and have not studied them in depth. The bagua disk outside was manageable, but this underground passage is considerably more complex.”

Yan Qing thought of the Three Kingdoms stories she had read. In this era, she did not know who had invented the bagua maze, but in that era, it was said to have been devised by Zhuge Liang.

Whoever invented it, the principles should be the same.

“I happen to know how a bagua maze should be broken, but I only know the theory, not how to apply it in practice.” Now that she thought about it, spending all those hours at home watching historical dramas did have its uses—and she could even still remember the dialogue from them.

“Tell me.” Shi Ting was mildly surprised.

“A bagua maze opens eight gates according to Rest, Life, Injury, Obstruction, View, Death, Fright, and Open. Enter from the due-east Life Gate, exit westward through the Rest Gate, then enter again from the due-north Open Gate—and the maze can be broken.” Yan Qing recalled the words spoken by Zhuge Liang in the drama. “Only now we don’t know where the Life Gate, Rest Gate, and Open Gate are.”

The underground passage had eight exits but no markings of any kind. Once inside, one immediately lost all sense of direction and could not distinguish east from west, north from south.

“Without finding due east, we cannot know which is the Life Gate.” Shi Ting frowned deeply.

“Let’s look around. I think the person who designed this passage faced the same problem we do when simply entering it—he would also lose his sense of direction. He would not have left himself without a way out. Among these eight tunnel exits, there must be some kind of marker.”

“All right.” Shi Ting took Yan Qing’s hand. “Don’t let go. Don’t leave my side for even a moment.”

If the two of them became separated at this moment, they might never find each other again.

Yan Qing’s hand was clasped tightly in Shi Ting’s palm. She could feel the cool dampness of his palm. She was used to seeing him composed and in command of every situation, but this time, she knew he had no certainty at all.

If they were truly trapped here, they would be beyond all help, left to slowly starve and die of thirst.