The Thing Beneath the Lake

Thanks to the reader "Ironwood of Spirit Milk Pool" for the capsule. Here's an extra chapter!

Sunday, seven in the morning.

Zhang Wen was awakened by a rooster.

The rooster at Angus's house had an even louder voice than those at Hogwarts. Standing on the fence outside the window, it proclaimed at the top of its lungs to the Scottish Highlands that dawn had arrived.

Zhang Wen turned over and found himself sleeping on the sofa in Angus's living room. Two sleeping bags had been laid out on the floor beside him—one for Harry and one for Malfoy.

Harry was already awake and quietly putting on his shoes.

Malfoy was still in his sleeping bag, his blond hair a tangled mess and his mouth slightly open. He had probably never slept on the floor in his life. When they had set out the sleeping bags last night, he had looked as though someone had asked him to clean an owlery with his bare hands.

"Malfoy," Zhang Wen called.

No response.

"Mr. Malfoy."

Still no response.

Artoria came over from the kitchen. She was already fully dressed—she had probably been up since five. She held a cup of tea in her hand.

She glanced at Malfoy on the floor.

Then she crouched down and said one word into Malfoy's ear.

"Up."

Malfoy shot upright, his eyes wide.

"What happened?!"

"It's seven in the morning. Time to get up." Artoria straightened and took a sip of tea.

Malfoy clutched his pounding heart and looked at her accusingly.

"Could you perhaps—use a less frightening way—"

"That was the gentlest method." Artoria said. "In my homeland, we used cold water to wake knights who slept in."

Malfoy wisely shut his mouth.

Breakfast was oatmeal and fried eggs made by Angus.

It was a simple farmhouse meal. There was no feast covering the entire table like in Hogwarts's Great Hall, but it was hot and filling.

Artoria ate three bowls of oatmeal.

Angus stared at her empty bowl, dumbfounded.

"Does she... usually eat this much?" Angus quietly asked Zhang Wen.

"This is considered little."

Angus decided to make another pot.

Harry did not eat much, but he ate seriously. He was used to meager food—at the Dursleys' table, he had always been left with the least.

Malfoy stirred his oatmeal with his spoon for quite a while.

"What's wrong?" Zhang Wen asked.

"I've never had oatmeal," Malfoy said. There was no disdain in his tone, only confusion. "Breakfast at the Malfoy household is usually French crepes or smoked salmon."

"Give it a try."

Malfoy scooped up a spoonful and put it in his mouth. He chewed twice.

"...It's all right," he said.

Zhang Wen noticed that he silently took a second spoonful.

After breakfast, Zhang Wen held a brief planning meeting.

The location was Angus's living room. The four of them sat around the fireplace.

"Yesterday's preliminary investigation confirmed several things." Zhang Wen drew a rough map of the lake on a piece of parchment. "First, the target is at the bottom of the lake. It is at least four to five meters long. Second, it has active defensive awareness—it can detect and rebound a Detection Charm. Third, its magic is corrosive and is continuously polluting the surrounding environment."

"Fourth," Artoria added, "it chooses to move at night. The Alarm Charm I set off went off twice last night—at two and four in the morning. Both times, there were brief ripples on the lake, but it did not come ashore."

"It was probing us?" Harry asked.

"Observing us," Artoria said. "Like a hunter assessing its prey's behavior. It knows new visitors have arrived on the shore and is judging whether we pose a threat."

Malfoy tightened his grip around his teacup.

"Today's plan has two steps," Zhang Wen said. "This morning, I'll take Harry Potter to the lakeshore for detailed magical sampling. By analyzing the residual magical signatures, we can narrow down what kind of creature it is. This afternoon, we'll visit the villagers and gather eyewitness accounts."

"What about me?" Malfoy asked.

"You'll stay near Angus's house with Assistant Pendragon," Zhang Wen said. "Your task is to help Assistant Pendragon draw a topographical map of this area—mark the positions of the lake, pastures, roads, and houses. This map will be used for the follow-up operation plan."

Malfoy's mouth moved. He probably wanted to say that drawing maps was work for servants. But he glanced at Artoria and swallowed the words.

Yesterday's conversation on the bus was clearly still echoing in his mind.

"I can do it," he said.

Nine in the morning.

Zhang Wen and Harry arrived at the lakeshore.

Glenmore Lake did not look as terrifying in daylight as it had the night before. Beneath the overcast sky, its surface was grayish blue, while the surrounding Highland hills were covered in withered yellow grass and dark brown shrubs.

But the dead zone looked even more glaring beneath the sunlight.

A vast stretch of gray wasteland was embedded in the green slope, its boundary so clear that it looked as though someone had drawn it with a ruler. The corrosion had spread another circle since last night—by roughly two or three square meters.

"It's expanding every day." Harry crouched at the edge of the dead zone, frowning. "At this rate—if it keeps going—"

"In a month, it'll cover the entire lakeshore. In three months, it may spread to the village," Zhang Wen finished for him.

Harry's expression grew serious.

Zhang Wen raised his wand and cast a series of detection spells at the dead zone. Each spell produced a different-colored light, forming various patterns across the gray soil.

"What are you doing?" Harry leaned closer to look.

"Magical spectrum analysis," Zhang Wen explained. "Every magical creature has unique magical characteristics—like fingerprints. By analyzing the frequency, intensity, and decay pattern of residual magic, we can determine what category it belongs to."

"We haven't learned that from the textbooks."

"The textbooks don't teach it. It's a field skill." Zhang Wen recorded data as he cast spells. "Quirrell's classes didn't teach it, and Lockhart's certainly wouldn't. Most Defense Against the Dark Arts professors only teach students how to deal with known threats. But a true defensive magic expert needs to know how to identify unknown threats."

Harry carefully watched every step Zhang Wen took.

"Can I try?"

"Wait until I finish the sampling," Zhang Wen said. "Then I'll teach you a basic detection spell."

It took him around twenty minutes to complete the sampling.

The results were interesting.

"The magical frequency is low—lower than that of most known magical creatures." Zhang Wen looked at the recorded data. "The decay pattern is nonlinear, which means this magical source was not naturally formed."

"What does that mean?"

"Natural magical creatures—such as Unicorns, Phoenixes, and Basilisks—their magical decay is linear, like a smooth curve. But this thing's magical decay fluctuates, with obvious irregular rises and falls."

Zhang Wen frowned.

"This pattern usually appears in creatures that have been altered by external forces."

"Altered?" Harry's eyes widened. "You mean someone deliberately turned it into what it is now?"

"Possibly. It could also have been an accident—a byproduct of some dark magic experiment, or an ordinary creature contaminated by a cursed object."

Zhang Wen put away the records and stood.

"Mr. Potter, come here. I'll teach you a basic Detection Charm."

For the next half hour, Zhang Wen taught Harry the simplest magical detection spell step by step—the "Revealing Charm." This spell could make hidden traces of magic briefly emit visible light.

Harry learned quickly. On his third attempt, he succeeded—dark purple patterns surfaced across the soil of the dead zone, stretching in the direction of the corrosion toward the center of the lake.

"I see them." Harry stared at the purple lines. "They all point toward the center of the lake."

"Because the magical source is at the bottom of the lake. All the corrosion is spreading outward from the lake's center."

Harry followed the purple patterns toward the water.

The gray-blue surface was unnervingly calm.

"Professor Zhang," Harry suddenly said.

"Hmm?"

"You said before that it might have been altered. If someone deliberately created this thing—could that person still be nearby?"

Zhang Wen looked at Harry.

This twelve-year-old boy had not been thinking about how to defeat this monster.

He had been thinking about who created this monster.

He had moved from tactical thinking to strategic thinking.

"Good question," Zhang Wen said. "When we visit the villagers this afternoon, that will be one of our main lines of inquiry."

Meanwhile.

On the slope behind Angus's house.

Artoria was drawing a topographical map with Malfoy.

Artoria's mapmaking skills had been trained in Camelot—drawing the terrain of a battlefield before marching to war was a commander's basic duty. She used her wand to draw precise contour lines, waterways, and building markers on parchment.

Malfoy followed behind her, using a compass to measure bearings.

At first, he did not even know how to use a compass properly—pure-blood wizarding families had never taught him how to use any Muggle tools.

"Why does this needle keep pointing in the same direction?" Malfoy held up the compass and frowned.

"The Earth's magnetic field. The North Pole is in that direction," Artoria said.

"What magnetic field?"

"Did you fail Muggle Studies?"

"I didn't take Muggle Studies," Malfoy replied with complete confidence.

"Then you are missing an important part of your knowledge," Artoria said. "The magical world and the Muggle world share the same physical space. Understanding the fundamental principles of the Muggle world is equally valuable to wizards."

Malfoy's mouth fell open.

In the education he had received since childhood, "Muggle things" had been synonymous with "inferior things unworthy of understanding." Now, someone he sincerely respected was telling him that this belief was wrong.

He did not argue.

Holding the compass, he seriously learned how to read bearings.

Artoria taught with great patience. Just as when she taught Neville Longbottom swordsmanship—her patience was not the gentle sort, but strict and clear. She explained every step plainly and accepted no "close enough."

"Southwest, two hundred and ten degrees. The position of that stone house," Malfoy said, holding the compass.

"Two hundred and fifteen degrees. You are off by five degrees."

"What does five degrees matter—"

"On a battlefield, a five-degree deviation means a shell lands on your own men's heads."

Malfoy swallowed and recalibrated.

"Two hundred and fifteen degrees."

"Correct. Mark it."

Malfoy carefully marked the position on the parchment. His handwriting was neat—he had probably been trained by private tutors from childhood.

The two of them walked across the slope for nearly an hour. The topographical map gradually took shape—the lake, village, pastures, slopes, paths, and bridges were all clearly marked on the parchment.

"Finished." Malfoy looked at the completed map, with a hint of accomplishment in his voice that even he had not noticed.

Artoria examined the map.

"The precision is acceptable," she said. "A few points need minor adjustments—the church is about ten meters too far east, and you missed a marker at the corner of the pasture fence."

Malfoy's face reddened slightly. He picked up his quill and made the corrections.

"But the overall structure is clear, and the proportions are accurate," Artoria added. "For a first attempt, it passes."

Malfoy's hand paused.

The words "it passes," coming from Artoria, carried about the same weight as an "Outstanding" from Dumbledore.

"Thank you, Assistant Pendragon," Malfoy said. His voice was quiet, but sincere.

Artoria glanced at him and nodded.

At noon, the four of them met at Angus's house.

Lunch was bread, cheese, and soup made by Angus. Artoria drank four bowls of soup. Angus had already learned to prepare an extra portion in advance.

After the meal, Zhang Wen shared the morning's findings with everyone.

"The magical samples indicate that this creature was most likely altered by human intervention." He spread the data across the table. "This afternoon, we'll visit the village. We'll focus on two things—first, whether anything similar has ever appeared in this lake before. Second, whether any outsiders have been active near the village recently."

"I'll go with you," Harry said.

"I'll go too," Malfoy said.

Zhang Wen looked at them. The two had unexpectedly spoken almost the same words at the same time, then glared at each other.

"You'll both go," Zhang Wen said. "Split up. Harry Potter will take the eastern half of the village, and Malfoy will take the western half. Each of you must visit at least three households. Ask the same questions: 'Have you seen anything strange near the lake recently? Have any outsiders come by?'"

"Alone?" Malfoy hesitated.

"You're twelve. Knocking on doors and asking a few questions in a Muggle village doesn't require an adult accompanying you," Zhang Wen said. "This is also part of your assignment—having a normal conversation with Muggles."

Malfoy's expression became quite spectacular.

"I've never—formally—spoken to a Muggle before."

"Then today is a good opportunity."

"What should I say?"

"Just treat them like normal people. Because they are normal people."

Malfoy took a deep breath.

His expression reminded Zhang Wen of Neville's first time stepping onto a dueling platform—nervous, uncertain, but gritting his teeth to do it anyway.

The difference was that Neville had faced an opponent.

Malfoy was facing the prejudices he had carried all his life.

In a sense, Malfoy's step was even harder.

The afternoon visits lasted three hours.

Harry's side went smoothly. He had grown up in a Muggle environment, so chatting with the villagers posed no difficulty. He visited four households and gathered the following information:

First, Glenmore Lake had never shown anything like this before. The older villagers said the lake was "quiet as death," and that there had not even been any large fish in it for decades.

Second, around two months ago—at the end of August—someone saw a person in a black cloak wandering by the lake. It was late at night, and the witness was an elderly woman suffering from insomnia. From her window, she saw the person standing by the lake, making "some strange movements," before disappearing.

Third, about a week after the black-cloaked person appeared, the first sheep vanished.

As for Malfoy—

Zhang Wen nearly laughed out loud when he received Malfoy's report.

Malfoy had visited three households. The first belonged to an elderly couple. He stood at their door for a full two minutes before finally knocking. When the old woman opened it and asked, "Who are you looking for?" Malfoy said, "I'm here to conduct an investigation." She mistook him for a government official, warmly invited him in for tea, and then spent forty minutes complaining that nobody would repair the potholes in the road.

Malfoy patiently listened to every word.

"You listened to forty minutes of complaints about potholes?" Zhang Wen asked incredulously.

"She just kept talking. I couldn't find an opening to interrupt."

"Did you get anything useful?"

"Yes. In the middle of her complaints, she mentioned that her husband found something strange by the lake last month. A black stone, very smooth on the surface, and 'freezing cold to the touch.' Her husband brought it home and put it on the mantelpiece. Then he had nightmares that night. The next day, the stone was gone."

Zhang Wen's smile vanished.

"The stone disappeared?"

"She said the mantelpiece was empty when they woke up. The windows were shut, the door was locked. The stone disappeared on its own."

Zhang Wen and Artoria exchanged a look.

A black stone that gave people nightmares, felt painfully cold after contact, and could disappear on its own. "A Dark Magic medium," Artoria said. Zhang Wen nodded, and the puzzle slowly began to take shape.

Two months ago, a person in a black cloak came to the lake and performed "strange movements." Afterward, an unknown creature appeared in the lake. Stones imbued with Dark Magic appeared by the shore—possibly remnants of some ritual, or perhaps ritual mediums.

"Someone put something in this lake," Zhang Wen said. "The black-cloaked person performed some sort of ritual—possibly a summoning, possibly a release. That black stone was most likely part of the ritual."

"Who would do something like that?" Harry asked.

"That is exactly what we need to find out."

Malfoy sat nearby, his expression much heavier than it had been that morning.

"That old woman's husband..." he suddenly said. "He had nightmares after touching the stone. How is he now?"

Zhang Wen looked at him.

"I asked," Malfoy said. "She said he has been having frequent headaches for the past month, and his memory has gotten worse. She assumed it was just old age."

The room fell silent for a moment.

"He was affected by the stone's magic," Zhang Wen said gravely. "A characteristic of corrosive Dark Magic—contact causes lasting mental damage." Zhang Wen noticed Malfoy's tone. It was not This is interesting or What does this have to do with me? It was Can he be cured?

A sincere question about the health of an elderly Muggle he had never met.

"It will need further examination," Zhang Wen said. "But if the contact was only brief, the damage should not be too severe. Once I return to Hogwarts, I can have Madam Pomfrey prepare some potions to repair mental damage and send them over."

Malfoy nodded. He did not say thank you, nor did he say anything else. But his expression showed Zhang Wen something.

A twelve-year-old pure-blood heir was worrying about an elderly Muggle he had never met.

If Lucius Malfoy saw this, he would probably fall out of his chair in fury.

That evening.

The four of them sat in Angus's living room around the fireplace, sorting through the day's findings.

Zhang Wen drew a timeline on a sheet of parchment.

"Late August—the black-cloaked person appeared by the lake and conducted some sort of ritual."

"One week later—the first sheep disappeared."

"September to October—the creature gradually became more active at the bottom of the lake, and the area of corruption continued expanding."

"Mid-October—Angus discovered the anomaly and asked Professor McGonagall for help."

"What we are still missing..." Zhang Wen drew several question marks on the page. "The identity of the black-cloaked person. The exact nature of the ritual. The creature's precise species. And its weakness."

"I have some ideas about its weakness." Artoria set down her teacup. "If this creature truly resembles the Afanc from British legends—a water-dwelling monster—then it should have a natural aversion to fire and sunlight. Its choice to act at night supports that."

"Fire and sunlight." Zhang Wen wrote that down. "Anything else?"

"One method is mentioned in legends of the Afanc—sealing it with iron. Iron has properties that suppress Dark Magic in many magical systems. If the creature is sensitive to iron, we can use iron chains or iron spears to limit its movements."

"The Scottish Highlands do not lack iron." Zhang Wen looked at Angus. "Is there a blacksmith in your village?"

"There is," Angus said. "Old Mackenzie at the east end of the village. He has been a blacksmith all his life. He can make anything."

"I'll go to him tomorrow and commission a few things." Zhang Wen added a line to his list.

"There is one more thing," Artoria said. "That black stone that disappeared."

Everyone looked at her.

"If the stone was a ritual medium, then there are only two possibilities for its disappearance. Either someone took it away, or it returned to the caster by itself."

"If it is the latter—"

"Then the caster can remotely control ritual objects. It also means he has an ongoing connection with this creature."

Zhang Wen frowned.

An ongoing connection meant the caster might be remotely controlling the creature. The black-cloaked person might have already left the Scottish Highlands, but his influence remained—through that thing at the bottom of the lake.

"This is more complicated than I expected," Zhang Wen said, leaning back in his chair. "It may not be just a Dark Magical Creature problem. Someone may be manipulating things from behind the scenes."

"What do we do, then?" Harry asked.

"We deal with the immediate threat first," Zhang Wen said. "Whether there is someone behind it or not, the thing in the lake is threatening this village. Protecting the villagers is the priority. We can investigate whoever is behind it afterward."

"Continue investigating after we return to Hogwarts?"

"Yes. Our time out here is limited—we have to head back tomorrow afternoon. But the investigation will not stop. I'll bring the magical samples back for more detailed analysis, and I'll ask Dumbledore to check whether there are records of similar cases."

Zhang Wen looked at the two students.

"Potter, Malfoy, you both did well today."

Harry gave a shy smile.

The corner of Malfoy's mouth moved—just barely, but it did move.

"There is one last task tomorrow morning," Zhang Wen said. "I'm setting up a long-term monitoring system by the lake—several fixed Detection Charm anchor points to continuously track the creature's activity patterns. The system will automatically send the data to Hogwarts every day. Even when we are not here, we will be able to keep track of the situation in real time."

"Remote monitoring," Harry said. "Like Muggle surveillance cameras?"

"More or less. Except this records magical fluctuations."

"Smart," Harry said.

"Basic," Artoria corrected. "Every military operation requires continued intelligence support. If you lose awareness of the battlefield after retreating, you might as well blind yourself in one eye."

Sometimes Zhang Wen felt that Artoria should teach a class at Hogwarts called "Introduction to Warfare." The things she casually said were enough to fill half a textbook.

After dinner.

Harry and Malfoy had both returned to the living room to sleep. Angus had gone upstairs as well.

Only Zhang Wen and Artoria remained in the kitchen.

Zhang Wen was washing dishes beside the stove—he had offered to do it himself. Angus had been busy all day and deserved a rest. Artoria sat at the small kitchen table, making final notes on the map she had drawn that day.

The kitchen was tiny. The fire in the hearth made it pleasantly warm. Outside the window lay the night sky of the Scottish Highlands—without the glow of city lights, the stars were so dense they made his scalp tingle.

"Malfoy asked about that elderly Muggle's health today," Zhang Wen said as he washed the dishes.

"I heard."

"Do you think his changes are real?"

Artoria thought for a moment.

"There are two kinds of change in people. One is when external pressure forces them to alter their behavior—they return to normal once the pressure disappears. The other is when their inner understanding changes. That kind of change is irreversible."

"Which kind is Malfoy's?"

"For now, he is closer to the first kind. His behavior is changing, but his understanding has not fully caught up yet. However—"

She paused.

"When he asked, 'Can he be cured?' there was genuine concern in his eyes. It was not an act."

"So he might turn into the second kind."

"He might. But it will take time and more experiences."

Zhang Wen placed the last bowl on the drying rack.

He turned and leaned against the stove, watching Artoria mark the map at the table. Firelight fell across her face from the side, outlining her profile with sharp clarity.

"You were very patient when you taught Malfoy how to use a compass today," he said.

"Teaching requires patience."

"You are patient when you teach Neville Longbottom swordsmanship. You are patient when you teach Hermione how to anticipate. You are patient with every student."

Artoria looked up at him.

"What are you trying to say?"

"I was thinking... it seems like you really enjoy teaching people."

Artoria's pen paused.

"Back in Camelot, I did not have the opportunity to do this," she said. "A king's duty was to make decisions, give orders, and bear the consequences. Training knights was handled by others—Merlin, Sir Kay, Bedivere."

"But you wanted to."

Artoria fell silent for two seconds.

"Perhaps," she said. "Teaching others to become stronger—watching someone go from unable to able, from weak to strong—that feeling..."

She seemed to be searching for the right word.

"Meaningful?" Zhang Wen offered.

"Meaningful," Artoria repeated. There was a warmth in her voice that she might not have noticed herself. "In Camelot, I protected the people. Here, I teach people to protect themselves. The latter may be more—"

"More lasting," Zhang Wen said.

Artoria looked at him.

"You always manage to finish what I was about to say."

"Tacit understanding."

The kitchen fell quiet for a moment after he said those words.

The fire crackled.

Artoria lowered her head and continued marking the map.

"Do you need help with tomorrow's monitoring system?" she asked, steering the conversation back on track.

"I need you to help secure the anchor points. We need to place a marker stake at each of the lake's four directions."

"I'll get up at five tomorrow to make them."

"You do not need to get up that early—"

"I'll get up at five to make the marker stakes, train Malfoy to run at six, and eat breakfast at seven."

"You assigned Malfoy running?"

"He was out of breath after climbing the hillside for an hour yesterday. His stamina needs improvement."

"He will protest."

"He can protest. But he will run."

Zhang Wen smiled.

The Knight King's physical training plan had extended from Hogwarts to the Scottish Highlands. Malfoy probably had not expected this "field study" to include early-morning runs.

"Then should I run too?" Zhang Wen asked tentatively.

Artoria gave him a look.

"Your one-and-a-half-mile time only broke thirteen minutes last week. You cannot stop training every other day. Tomorrow happens to be a training day."

"We are carrying out a mission—"

"You can balance missions and training."

Zhang Wen sighed.

Some things truly never changed.

He turned off the kitchen light and returned to the living room with Artoria.

As they passed through the living room, he glanced at the two sleeping bags on the floor.

Harry was curled up in his sleeping bag, breathing evenly and sleeping deeply.

Malfoy's sleeping posture was better than the night before—at least he was no longer gripping the edge of his sleeping bag for dear life. His hand rested at his side, and the compass lay beside his fingertips.

He had placed the compass beside him while he slept.

Zhang Wen noticed the detail but said nothing.

A pure-blood boy who had never touched a Muggle tool had placed a compass beside his pillow.

Perhaps the change had already begun.

"Good night," Artoria said softly, heading for the small room Angus had arranged for her.

"Good night."

Zhang Wen lay down on the sofa and pulled the blanket over himself.

Outside the window, the starlight was painfully bright. In the direction of Glenmore Lake, everything was pitch-black.

The thing at the bottom of the lake was still there.

Tomorrow, they would set up the monitoring system and return to Hogwarts. But this matter was far from over. A mysterious person in a black cloak, an artificially altered creature, a black stone that could disappear—

Sooner or later, those fragments would form a complete picture.

Zhang Wen closed his eyes.

Five tomorrow morning. Running.

Before all the mysteries and threats, he first had to survive Artoria's training.

That might be the hardest part of the day.