Everyday Life of a Top Student at Hogwarts

Chapter 324 Returning to the Deep Pool to Seek Guidance from the Mentor

In mid-May, Hogwarts was warm, with sunlight streaming through the castle's tall windows into the corridors, creating a languid atmosphere. However, for the members of the Eyrie Squad, the air was thick with a silent tension and anticipation.

May 16th, evening.

As dusk settled, Karen, Wesley, Fabian, and Ernesto quietly left the castle and returned to their secluded spot along the shore of the Black Lake. The lake water, a deep, inky blue in the deepening twilight, was accompanied by a cool, misty breeze.

"Have you checked everything?" Karen asked in a low voice, while taking one last look at her equipment: her wand, dragon skin gloves, various testing tools and sample containers in a waterproof bag, a specially made isolation box with strong protective and isolation magic (for core items that might need to be taken out), and the improved, smaller, and longer-lasting portable sonic device.

"Don't worry, Karen." Wesley patted his bulging pockets. "Just like before, everything is ready."

Fabian handed over a small crystal bottle containing a few fresh pieces of dark algae: "Take this with you; you might need it in the lab. Be careful."

Ernesto looked up at the night sky, where stars were beginning to appear sporadically, and said with certainty, "The positions of the stars are approaching the calculated peak, and the energy field has begun to become active. You will have plenty of time."

Karen nodded, about to say something, when the air beside her seemed to shift slightly, and a familiar, tall, thin figure appeared there without warning, as if he had always been standing there.

Mr. Castor arrived. He wore a dark travel robe, and his grey eyes, sharp as an eagle in the twilight, swept over the four boys present.

"Professor," Karen and the other three greeted him respectfully.

Castor nodded slightly, his gaze landing directly on Karen: "Is everything ready?"

"Yes, teacher," Karen replied, handing over the specially made isolation box. "This was prepared as requested by you and Teacher Nico, and it has been enchanted with protective and magical isolation spells."

Castor took the box, his fingers lightly tracing the intricate runes on the lid. He carefully sensed it, then nodded. "Hmm, the strength is sufficient. If anything inside moves, it will at least buy us time to react." He handed the box back to Karen. "Keep it safe. How's the situation underwater?" This last question was directed at everyone.

"The mermaids don't seem to be letting their guard down, but their main patrol areas haven't changed," Karen replied. "At midday, I used sonar to scan our planned route, and so far, I haven't found any new dangerous creatures or traps."

The route is safe.

"Very good." Castor said no more. "Let's go."

Karen quickly prepared to enter the water. The two nodded to Wesley and his two companions on the shore, then simultaneously raised their wands and cast the Bubble Head Charm on themselves, before sliding into the icy lake one after the other.

Wesley, Fabian, and Ernesto held their breath, watching the two figures disappear beneath the dark surface of the lake, before quickly dispersing to their respective guard posts as planned.

Underwater, Karen led the way, with Castor close behind. With their previous experience and Karen's increasingly refined sonar perception, their stealth was smoother and more efficient. Karen occasionally used hand gestures to indicate the best route to her mentor behind her, avoiding the reef crevices and seaweed thickets that might conceal Grindylow, as well as the slow-moving magical halos in the distance representing patrolling mermaids.

The surrounding waters were still and deep, with only the sounds of their paddling and the faint gurgling of bubbles rising with their breath. The powerful water pressure enveloped their bodies, and the further they went, the dimmer the light became, until they were almost entirely reliant on their "True Eyes" and sonar to orient themselves.

Castor's swimming skills were clearly specially trained; his movements were fluid and effortless, allowing him to stay steadily behind Karen while remaining constantly alert to his surroundings.

About half an hour later, the familiar rock wall engraved with giant serpent runes reappeared in their "sight." The surrounding lake water seemed to have become even more "viscous," and the flow of magic power surged significantly, washing over their senses like an invisible tide. That deep and grand pulsation, seemingly from a thousand years ago, once again emanated from the depths of the rock wall, even clearer and more perceptible than before.

The two hovered before the rock face, waiting for the perfect moment. The eerie silence returned; even the smallest aquatic plankton seemed to have distanced themselves from this area of ​​turbulent energy.

In the silent wait, Karen couldn't help but turn around and, through magical communication, ask Castor, who was standing nearby, the question that had been lingering in his mind for so long: "Professor, why did Slytherin make the laboratory entrance only open during specific celestial events? Isn't that—very inconvenient? How does he usually get in and out?"

Castor's grey eyes turned to him, seemingly unsurprised by the question. He hesitated for a moment before replying, "Nicole and I discussed this. We believe it's quite possible that this wasn't the norm in Slytherin at the time."

He paused, seemingly organizing his thoughts to make it easier for Karen to understand: "Imagine this is an extremely sophisticated alchemical construct or magical space, buried deep at the bottom of a lake, having existed for millennia. It requires energy to maintain its basic structure, especially the magic circles that expand the space and preserve experimental materials. When Slytherin personally maintained and used it, he must have had a more convenient way of opening it, perhaps based on bloodline or a specific token, and he could replenish its energy at any time."

"But after Slytherin left or ceased maintaining it for other reasons, the laboratory's energy system likely automatically entered a very low-power hibernation mode in order to survive as long as possible." It shut down most non-essential functions, maintaining only the most core protection and preservation mechanisms, and instead relied on absorbing periodic, powerful natural magical fluctuations from the outside world—such as magical tides caused by specific celestial phenomena—to replenish its energy, and periodically "awaken" for a period of time.

What we are seeing now is perhaps its state under this "energy-saving mode". The entrance only appears briefly when it absorbs enough energy.

The entrance we're entering now is merely a brief window opened for us by utilizing the energy-saving mechanism it has built up over millennia. During my travels in my younger days, I saw similar ancient ruins that would manifest under specific conditions, but most were severely damaged. Such well-preserved sites are extremely rare; Salazar Slytherin truly lives up to its reputation.

Karen suddenly understood. It wasn't that Slytherin had deliberately made the entrance so complicated; rather, the laboratory, after losing its owner, had stubbornly survived to this day in a "low-power mode" thanks to its ingenious design. This deepened his awe and respect for the ingenuity and long-term design of ancient magic, as well as Salazar Slytherin's own superb skills in magical architecture and alchemy.

"So that's how it is—it's incredible!" Karen couldn't help but exclaim.

Just then, the magical pulsation inside the rock wall reached its peak! The familiar giant serpent runes made of light reappeared out of thin air, and just like last time, they began to flicker at that complex and specific frequency, as if telling an ancient code.

Karen immediately focused his attention, gazing intently at the flickering runes. His "Eye of Truth" precisely captured the rhythm of each flash and the subtle shifts in magical power. He swiftly raised his wand, not pointing it at the rock wall, but manipulating the surrounding water and light elements to precisely mimic the runes' flickering rhythm!

He didn't need to imitate Parsley's speech again, because it had already been verified last time that the key to opening the entrance lay in understanding the "language" of this light frequency. Magic flowed from the tip of his staff, creating bright spots of light in the water in front of him, shimmering in sync with the runes on the rock walls.

The moment the last flash of light perfectly matched the rhythm of the rock wall runes, a whoosh!

A deep, resonant hum, as if from the abyss, resounded. The runes on the rock wall suddenly lit up, then quickly dimmed, and where the runes had been, the familiar, magically constructed archway reappeared, behind which stretched the waterless ground into the open space.

The entrance has reopened!

Karen and Castor exchanged a glance, and without any hesitation, they quickly swam into the archway one after the other.

Passing through the slightly cool energy membrane, the feeling of stepping onto the dry, cold stone ground again was still somewhat strange. The lake behind them was blocked by an invisible force, forming a huge water dome. The interior of the laboratory remained exactly as they had left it—silent, empty, and filled with the same peculiar smell that had remained unchanged for millennia, a mixture of dust, potion ingredients, and moisture.

The two turned quickly. Castor waved his wand, and a subtle ripple of magic swept across the entrance. He nodded. "The entrance is stable and will remain open for the duration of the peak. We have time for a more thorough investigation."

Entering Slytherin's secret laboratory for the second time, Cullen was more composed and focused than before. He knew that this time, they not only needed to observe more closely, but also to seek answers with new hypotheses in mind.