Mu Zhong was nearly beside himself. When Lin Sui’an said she was going to catch the real killer, he’d trotted after her the whole way, expecting some great revelation — only to find that the very first person Lin Sui’an sought out was Zhu Dachang. The look he gave Zhu Dachang after that was distinctly off.

Zhu Dachang had just finished being reprimanded by County Lieutenant Zhang over the Luo Shichuan case — Zhang had made it plain that the Su clan had sent people to verify Su Chengxian’s identity, and he needed the county office to clearly separate the Su clan’s name from any association with the killer. Zhu Dachang was still suffering a massive headache from it all. When he heard that Mu Zhong had come to call, he assumed the generous-hearted Sir Mu had come to help him clean up the mess, and he bustled out eagerly — only to be met with Mu Zhong’s cold, penetrating stare, which made him jump.

One look at Lin Sui’an’s expression, and Zhu Dachang’s liver quivered. With no warning, the phrase “I am the fish upon the chopping board” came to mind, and the faint echo of a pain in his neck — where Lin Sui’an had once grabbed him — began to make itself felt again.

“What can I do for you two?” Zhu Dachang asked, picking his words with care.

“I’d like to see the examination record for Su Chengxian,” Lin Sui’an said, then added, “Is Coroner Ding available?”

Zhu Dachang looked bewilderedly at Mu Zhong. Mu Zhong murmured, “Su Chengxian may not be the killer.”

Hearing that, Zhu Dachang’s spirits lifted at once. He quickly sent someone to fetch Coroner Ding and personally retrieved the examination record for Lin Sui’an.

Lin Sui’an skimmed the autopsy report. Given her rather tragic ability to read classical Chinese, she did not uncover anything particularly useful, and sighed involuntarily — which was enough to send Mu Zhong and Zhu Dachang into a state of considerable anxiety.

Mu Zhong: “Well?”

Zhu Dachang: “So Su Chengxian truly wasn’t the killer?”

Lin Sui’an: “County Lieutenant Zhu, could you explain the layout of the underground water channels in Nanpu County in more detail?”

Zhu Dachang of course agreed. He sketched a rough ward map of Nanpu County and explained as he drew. “Nanpu County has twelve wards. Two main east-west streets — Liren Street and West Road Street — both have wastewater channels. Of the three north-south streets, only Chunman Street has a channel. The wastewater channels connect to the Xichun River that encircles the city. There are six outlet points in total, but the channels large enough for an adult to enter follow a flow direction roughly like this—” He drew a clockwise line with his brush, originating from Qiandu Ward, running along West Road Street, turning onto Chunman Street, looping past the Eastern Market, entering Liren Street, and exiting the city through Yanren Ward.

Lin Sui’an: “Where exactly was Su Chengxian’s body found?”

Zhu Dachang marked the intersection of the Eastern Market and Chunman Road.

Lin Sui’an traced the ward map with her finger. “If Su Chengxian were trying to leave the city, he would have come out of Yanren Ward, gone around the Eastern Market, through Chunlu Ward and Lihui Ward, and then to the West Double Gate.”

“That’s wrong!” Zhu Dachang exclaimed. “If he left through Yanren Ward, Su Chengxian could only have fallen into the channel at Yanren Ward or on Liren Street along the north side of the Eastern Market. But if that were the case, his body would have been carried out of the city long ago — it couldn’t possibly appear against the current, upstream in the Chunman Street channel.”

“The place where he fell into the channel was not Yanren Ward,” Lin Sui’an said, “but Qiandu Ward.”

Zhu Dachang: “What?!”

Mu Zhong: “There is a scholar in Qiandu Ward named Wei Li who claims to have been with Su Chengxian the entire night of the fifteenth of the eighth month. Send people to investigate him and question the neighbors in the area as well.”

Zhu Dachang stared blankly for quite some time before coming back to himself and calling for Li Nili to lead several constables to Qiandu Ward. Li Nili had barely left when Coroner Ding drifted in like a shadow.

“Coroner Ding, when you examined Su Chengxian’s body, were there any unusual findings?” Lin Sui’an asked. “Even things unrelated to the cause of death.”

Coroner Ding was silent for a moment. “There were signs indicative of excessive physical depletion. Rectal tearing — ante-mortem injury, fresh wound, within two hours prior to death.”

Lin Sui’an: “Where is the… rectum?”

Coroner Ding: “Where waste is expelled.”

Mu Zhong buried his face in his hands. “Good ancestors above.”

Zhu Dachang paused, then understood. He looked deeply strange. “So Su Chengxian spent the entire night… so in the morning he left in a state of dizziness, weak-kneed, and stumbled into the channel by accident?”

“Hah. A fitting way for him to go.” Lin Sui’an turned and walked out of the county office.

Mu Zhong followed immediately. Zhu Dachang hesitated for half a breath, then decisively abandoned his troublesome case documents and became the second tail.

*

In truth, the moment Wei Li provided Su Chengxian’s alibi, Lin Sui’an had already known that Su Chengxian was not the killer. The reason she had still insisted on coming to the county office to verify the evidence with Zhu Dachang and Coroner Ding was simply that she had been holding onto a sliver of hope.

What if Wei Li was lying?

What if it was simply someone with the same name?

What if Wei Li had the date wrong?

Lin Sui’an had actually considered giving up on the investigation entirely. Su Chengxian was an out-and-out contemptible man and no great loss to the world. Having him be the killer might have been the best possible outcome for all the victims.

But she couldn’t stand it.

Even if Su Chengxian was contemptible, she couldn’t stand seeing him falsely accused of murder. She couldn’t stand the real killer walking free, congratulating himself on a flawless scheme, playing the innocent.

In the Luo compound’s inner courtyard, the osmanthus tree had lost its keeper. Its blossoms were falling — spent petals scattered across the ground — and the last thin breath of fragrance clung stubbornly to the air, as if Luo Shichuan’s final obsession were desperately winding itself around Lin Sui’an’s thoughts.

Su Chengxian’s memory had cleared him of suspicion. So what had Luo Shichuan’s memory been trying to say?

Lin Sui’an did not dare to speculate rashly, but she had an uneasy feeling — as though the truth concealed something that did not reflect Luo Shichuan’s true wishes.

“Lin Niangzi, are you coming here because—” Mu Zhong guessed, “the real killer is someone inside the Luo compound? He’s still here?”

Lin Sui’an did not answer. She had already deduced the killer’s identity. If this person was indeed the killer, then every earlier sense of wrongness would find its explanation.

The name of the killer was on the tip of her tongue. She only lacked the evidence.

“Lin Niangzi, the servant responsible for cleaning Luo Shichuan’s inner room has arrived.” Li Nili brought over a manservant past fifty years of age, who bowed in greeting.

Lin Sui’an nodded and produced the crime scene diagram from her sleeve. “Does the arrangement of the tea implements in this diagram differ at all from how Master Luo placed them in his lifetime?”

The servant examined the diagram carefully, then shook his head. “Aside from the wind-furnace being slightly to the left, nothing differs.”

“Besides yourself, who else was familiar with the arrangement of the tea implements?”

“The master did not like servants touching his tea implements. He also preferred to brew tea alone, and only those very close to him knew the arrangement.”

“After Luo Shichuan finished brewing tea each time, did he always leave the furnace chamber quite clean?”

The servant shook his head. “The master would leave a small amount of charcoal residue in the furnace to keep it warm and seasoned.”

Lin Sui’an nodded and dismissed the servant. She walked around the room with the diagram. After Luo Shichuan’s death, Luo Kou had not moved any of the furniture — she had only ordered the servants to clean and tidy, put away Luo Shichuan’s personal effects, and replace the main door.

The room was nearly identical to the crime scene. Lin Sui’an could almost see the ghost images superimposed before her eyes:

Luo Shichuan seated in a pool of blood with his back against the door… the bolt broken, the body slumping to the floor… Meng Man rushing in and throwing himself down, weeping… Luo Kou flinging herself over her father’s body, hands covered in blood…

Lin Sui’an closed her eyes for a moment, then turned to examine the newly replaced door. The thickness, height, material, grain, and bolt were almost identical to the original — only the small carved groove was absent.

The greatest trick in this case was the sealed room — and the place where the killer had left the most clues. Lin Sui’an had a feeling that the decisive evidence was hidden somewhere in the sealed-room puzzle.

But where?

She pulled the door shut, gave it a push, then pulled it open and shook it twice, then shut it again and examined the door seam. Just as she had predicted: the door and frame met flush without any gap. Lin Sui’an then tried to slide the bolt. Perhaps because she had not used it much, she fumbled with it for quite some time before managing to slide it home — and found that she had to brace both feet against the two door panels simultaneously before the bolt would slide in smoothly.

Wait.

Lin Sui’an pulled the bolt out and tried again. Her head felt as though it had been struck by an iron hammer, ringing loudly.

“Sir Mu! County Lieutenant Zhu!” Lin Sui’an called out sharply. “We are going to recreate the sealed room.”

Both men: “What?”

One incense-stick of time later, all three of them were drenched in sweat, staring at the stubborn bolt with expressions that had grown quite grim.

They had filed matching grooves into the bolt and the door panel, and following the method Lin Sui’an had previously theorized — bolting the door from outside — they had tried ten times in succession. Every single attempt had failed. Either the leather cord slipped out of the groove, or the bolt dropped to the floor, or the bolt simply refused to slide into place. Even with someone inside the room directing their movements, not one attempt succeeded.

“There is no need to continue. My reasoning was wrong,” Lin Sui’an said. “This method cannot produce the sealed room.”

Mu Zhong looked astonished. Zhu Dachang’s face drained of color and he jabbed his finger at Lin Sui’an and shouted, “So you are the real killer!”

Lin Sui’an shot him a ferocious look. “If this method doesn’t work, only one possibility remains.”

Mu Zhong: “What do you mean?”

“The bolt cannot be drawn from outside,” Lin Sui’an pulled the door shut and slid the bolt into place, “which means it was bolted from inside.”

Mu Zhong’s mouth fell open. Zhu Dachang shot backwards at full speed. “What — what — what are you going to do?! Lock the door and slaughter us all?!”

Mu Zhong stared at Lin Sui’an for a long moment, his expression shifting. “Could it be…”

Lin Sui’an closed her eyes and inclined her head slightly.

Zhu Dachang clasped his head. “To think that I, Zhu Dachang, a man of lifelong fame, am to die in such a shameful manner — Mother, Father, I have failed you — wah, wah, wah—”

Lin Sui’an opened the door. The light and shadow poured in brilliantly across her face, washing her vision in a warm amber glow. The osmanthus leaves rustled in the wind — and it sounded like Luo Shichuan’s low murmuring voice:

【I still remember, to this very day — that Mid-Autumn night with the full moon, the osmanthus in fierce bloom, its rich fragrance filling the air, and Kou’er and Man’er, their little faces caked in mud, presenting me with a tea kettle they had been hiding for days. The tea that night was truly fragrant…】

*

When Luo Kou was ushered into the inner hall, she found Mu Zhong, Zhu Dachang, and Lin Sui’an all present. County Lieutenant Zhu’s expression was muddled, Sixth Leader Mu was sighing and muttering, and strangest of all was Lin Sui’an — she had been gazing at the osmanthus tree in the garden, her eyes distant, her expression dazed, as if wrestling with some enormously difficult decision.

Luo Kou greeted them each in turn, looking a little puzzled. The constable had told her that County Lieutenant Zhu had asked for both her and her brother to come — yet there was no sign of Meng Man. She had been on the verge of asking, but after a moment’s reflection recalled that these past few days Meng Man had been arguing with her constantly over the household division. His absence was, in truth, a mild relief.

Before long, Meng Man arrived as well, also looking puzzled.

“Greetings to County Lieutenant Zhu and Sixth Leader Mu. What matter has brought us here, calling on both my sister and me?”

Mu Zhong looked at Lin Sui’an. Zhu Dachang coughed twice as a prompt.

Lin Sui’an seemed to start from a dream. Her quiet gaze rested on Luo Kou’s face for a moment — then she suddenly drew her blade and swung it at Meng Man. Everyone’s expression changed in an instant. Luo Kou’s scream had barely reached her own throat before Lin Sui’an’s blade stopped — three inches from Meng Man’s topknot.

Meng Man sat on the floor, his face a mask of shock and terror. His right hand was braced on the ground. His left arm was raised in front of his forehead as a shield. Fine beads of sweat had broken out at the tip of his nose.

Zhu Dachang gasped and jabbed a finger at Meng Man. “He — he — he — he — he—”

“He is left-handed.” Lin Sui’an sheathed her blade. “He simply conceals it in daily life, presenting himself as right-handed, but in a moment of genuine crisis, his instinct reverts to the left.”

Mu Zhong understood at once. “At the mourning hall, when he went to strike Luo Liulang — he used his left hand then too.”

Luo Kou: “Left hand or right — what does that matter?”

Lin Sui’an glanced at Zhu Dachang, who felt the pressure bearing down on him. He cleared his throat. “According to the coroner’s examination, the killer who stabbed Luo Shichuan was left-handed. We had assumed that only Su Chengxian in the Luo household was left-handed — but it seems we overlooked someone…”

“What are you saying?” Luo Kou’s voice trembled. “What exactly are you saying?!”

Meng Man rose to his feet and brushed the dust from his robes. “I heard that the Su clan recently dispatched people to Nanpu County to restore Su Chengxian’s reputation and clear the Su name. Could it be that the county office, unable to withstand the pressure of the Su clan, is looking for a scapegoat to whitewash the identity of Su Chengxian as a killer?”

At that, Meng Man let out a cold laugh. “I am an orphan, not entered in the Luo clan registry, with no position, no influence, and no patron. Is there anyone more suited to be a scapegoat? To wipe the name clean for a noble family, you have really gone to extraordinary lengths.”

Luo Kou’s face was filled with shock.

“Don’t listen to his nonsense — the Su clan may have that intent, but I never agreed!” Zhu Dachang said. “How could I, as the parent-official of Nanpu County, smear an innocent person for personal gain? If word got out, how would I face my parents and neighbors?!”

“Sir Meng Man says Su Chengxian is the killer — do you have evidence?” Lin Sui’an asked.

“That is an odd question for Lin Niangzi to ask,” Meng Man said, with something between a smile and a sneer. “It was you who broke the sealed-room puzzle, you who found the physical evidence outside Su Chengxian’s window, and you who established Su Chengxian as the killer. Why are you asking me for evidence?”

“Because Su Chengxian was not in the Luo compound that night. He was in Qiandu Ward the entire night.”

Meng Man’s face changed sharply. “What did you say?! Impossible!”

“Why impossible? Because Su Chengxian was an outsider with nowhere to go but the Luo compound? Or because Qiandu Ward is all local residents, who would never take in a stranger overnight?”

“Where was he staying? Is there a witness? What was Su Chengxian doing in Qiandu Ward the entire night?!”

Luo Kou: “Yes — is there a witness?!”

At those words, both Mu Zhong and Zhu Dachang fell silent. One rubbed his forehead, the other touched his nose — neither quite knew how to explain.

Meng Man laughed coldly. “So you fabricated it after all!”

“Su Chengxian had a lover in Qiandu Ward, a man named Wei Li. They were together the entire night of the fifteenth of the eighth month. There is physical evidence and a witness.”

Meng Man’s cold smile froze on his face. Luo Kou’s whole body swayed violently and she sank to her knees. Zhu Dachang hurried over and helped her to a seat. Mu Zhong frowned quite disapprovingly at Lin Sui’an; Lin Sui’an ignored him.

Such matters were like an infected abscess. If not lanced promptly, they would one day fester into something far worse.

“On the day Luo Shichuan’s body was discovered, several details struck me as wrong and out of place. First: the tea implements were arranged exactly as Luo Shichuan always arranged them, without any difference. There are two possible explanations. The first is that Luo Shichuan had not touched the implements at all that night. But there was no charcoal residue of any kind left in the wind-furnace. The servant who attended Luo Shichuan said that the master never allowed anyone to touch his tea implements, that he cleaned and maintained them all himself, and that he always left charcoal residue in the furnace to keep it warm and well-seasoned after each brewing.”

Mu Zhong: “Which means someone else touched the furnace — and that person was not Luo Shichuan.”

Zhu Dachang: “But the arrangement of the tea implements was unchanged, wasn’t it?”

Lin Sui’an: “That brings us to the second possibility: Luo Shichuan brewed tea that night to receive a guest, and was unexpectedly killed. In order to erase any trace of having shared tea with Luo Shichuan, the killer flawlessly restored the implements to their original positions.”

Zhu Dachang: “I understand! This person must have been someone Luo Shichuan trusted deeply and was very close to! Which means only the Luo young lady and—”

Luo Kou stared at Meng Man in a daze, her face a picture of disbelief. Meng Man’s face twitched; he ground his teeth. “Anyone with enough determination could memorize the arrangement of tea implements!”

Lin Sui’an did not follow that thread. She pressed on with her own line of reasoning. “But this creates a further contradiction. If this person knew Luo Shichuan’s habits so well, why did they not leave charcoal residue in the furnace? If they had, there would have been no flaw. I therefore suspect they had some reason to clear the furnace entirely — for instance, they had burned something in it, but hadn’t burned it completely.”

Meng Man’s pupils contracted sharply. His fists tightened.

Lin Sui’an: “The second inconsistency was in the reactions upon discovering Luo Shichuan’s body. The first person through the door was Meng Man — he prostrated himself and wept inconsolably.”

Zhu Dachang: “What’s wrong with that?”

“Nothing by itself. But compared to Luo Kou’s reaction, it is deeply wrong.” Lin Sui’an said. “When Luo Kou saw her father lying inside, her first instinct was to check his physical condition — she did not even notice she had covered her hands in blood.”

Mu Zhong: “I remember it clearly — Meng Man never checked whether Luo Shichuan was alive or dead. He simply prostrated himself and wept at once, as if he already knew Luo Shichuan was beyond saving.”

Meng Man: “Absurd — there was blood everywhere. Anyone with eyes could see the master was long dead!”

“He makes a fair point…” Zhu Dachang began, then caught Lin Sui’an’s gaze and immediately pulled his neck in and shut his mouth.

“But Luo Kou did not see it that way,” Lin Sui’an said coldly. “Was she blind? Was she slow? Neither. She couldn’t see clearly because she was out of her mind with love and fear. If you see your closest loved one lying in a pool of blood, is not your first instinct to try to save them?”

Meng Man: “Ridiculous — the master’s body had already gone cold and rigid—”

“How did you know he was cold and rigid? You did not touch him once from beginning to end. Your hands were clean and white — not a single drop of blood. Your beloved father lay dead before your eyes, and you did not dare even to touch him. Was it not because of a guilty conscience?” Lin Sui’an said.

“Sophistry! This is meaningless!” Meng Man trembled all over. “You also never touched the master’s body. Your hands were clean too. Are you guilty as well?! And what about the sealed room — how do you explain that?! What about the leather cord and the fire-starter found outside Su Chengxian’s window?!”

Lin Sui’an drew a breath, reminding herself to stay calm and not let Meng Man dictate the pace of this exchange. “If we want to know what the killer did, perhaps we should reconstruct the scene step by step.”

“On the night of the fifteenth of the eighth month, as darkness fell, the inner courtyard of the Luo compound had been set out with tables, chairs, and fresh fruit for the moon-viewing. There were also the dried grapes that the Luo young lady loved. Inside the inner room, Luo Shichuan was brewing tea and receiving a guest. The two of them were talking pleasantly — until Luo Shichuan suddenly produced an object that drove the guest into a rage beyond any limit.”