The incident involving Filch's attack caused quite a stir.
For several days, the students could talk of nothing else, constantly discussing the assault.
Most of them, however, approached it with a sense of schadenfreude.
Nobody liked Filch!
Filch's behavior only ensured that everyone remembered the incident. He seemed to be severely traumatized, shambling around the castle like a zombie, broom in hand, cleaning mechanically.
He muttered incessantly under his breath: "Harry Potter."
Many students began viewing Harry as a hero for standing up to Filch.
Mrs. Norris's behavior was the strangest of all—she refused to go near Filch and spent her nights sleeping on a cat tree William had set up in the Boba Tea Room.
To accommodate Mrs. Norris, William even prepared a cozy little nest, feeding her with care and attention. Ideally, she'd eventually have kittens there without Filch ever finding out.
Although Dumbledore insisted that the Chamber of Secrets wasn't important, William was still determined to investigate and see if he could uncover anything.
In truth, he already had a target in mind, making it not too difficult to locate the Chamber.
For instance... a certain secret passage!
Hogwarts had many secret passages.
Some were winding and concealed by dense foliage; others were hidden in deep ravines with babbling brooks outside.
Each passage had its own character, some shallow, some deep, some spacious, some narrow, and required different approaches to enter.
For example, on the seventh-floor corridor of Hogwarts Castle, there was a portrait of the Arithmancy scholar Vindictus Viridian.
Behind this portrait lay a secret passage leading to the portrait gallery, where walls were lined with Hogwarts paintings. The password was "Snafflejack."
William had visited it many times, discussing potions and spells with several of the headmasters depicted there, gaining significant insights.
Currently, there were seven known secret passages leading to Hogsmeade.
In their first year, the twins often used the one behind the mirror on the fifth floor.
However, they stopped using it after discovering a shed snakeskin there.
Dumbledore speculated that the basilisk was the monster from the Chamber of Secrets, and since the basilisk had shed its skin in that passage, it was likely connected to the Chamber.
Returning to the passage now, William was struck by how much it resembled a dungeon rather than a mere secret passage.
Indeed, it looked like an underground palace, with a main corridor flanked by countless small chambers and pathways.
Before long, they reached the structure directly beneath the circular hall.
By the light, they could make out the solid forms of forty Doric columns supporting the marble floor above.
The architecture of this underground palace bore no trace of time's passage. The relief carvings were lifelike, and the colonnades were adorned with intricate ancient runes.
When William had first come here as a first-year student, he hadn't understood these inscriptions. Now, however, he could read them.
"What do they say?" Cedric asked.
He had also studied ancient runes, but his knowledge was limited to vocabulary, making it impossible for him to decipher the meaning.
"These pillars are inscribed with protective magic to prevent this structure from being damaged," William explained.
He couldn't glean any information about the building's specific purpose from the inscriptions.
However, it was undoubtedly a significant secret meeting place during the era of the Founders.
It seemed the Founders had been engaged in something more than education, they might have been running pyramid schemes on the side.
The group continued forward until they reached an underground lake.
At the center of the lake was a small island, upon which stood a pyramid.
The pyramid, about two stories high, was made of granite. Under the glow of magical lamps, its polished surfaces gleamed with precision and beauty.
The magic surrounding the area ensured that no one could approach the island.
Since they couldn't get closer, they didn't linger and proceeded toward the place where the snakeskin had been found.
"This is the spot," one of the twins said.
They stood in a corridor littered with the bones of small animals, evidence that the basilisk had hunted here.
Moving further ahead, they saw the coiled outline of a massive creature.
It was an enormous snakeskin, pale in color and clearly shed long ago.
"Could there be another basilisk in the Chamber?" Fred asked worriedly.
If they found the Chamber only to discover another basilisk inside, they could easily meet a grim fate.
"Unlikely," William reasoned, "From a food supply perspective, Hogwarts could only sustain one basilisk."
The group chuckled nervously, and George pulled a rooster out of his enchanted ring.
The crow of a rooster was fatal to basilisks.
"Where'd you get that?" William asked, surprised.
"From Hagrid. I snuck it out," George replied excitedly "Look how plump it is! After we find the Chamber, we can have roast chicken!"
William nodded in agreement, he had plenty of spices on hand for a barbecue.
As they continued through the corridor, Cedric asked curiously, "William, I read in the library that basilisks are created by placing a chicken egg under a toad to hatch.
"If the method is so simple, why aren't there more basilisks? Newt Scamander's book says England hasn't seen a basilisk for centuries."
The twins also looked to William for an explanation.
William paused before answering, "Not just any egg will do, it has to be a rooster's egg."
"Roosters lay eggs?" Fred asked, puzzled.
"Not in the usual sense," William clarified. "It's a mixture of a rooster's reproductive matter and feces.
"This mixture takes seven years to mature into something egg-like. During this time, the rooster stops eating and becomes restless, constantly scratching at nests.
"On the brightest night of Sirius, it secretly lays the egg.
"This egg is called a 'basilisk egg.'"
William had learned this obscure method of basilisk creation from a book in the Restricted Section.
The vast world of magic contained many cryptic texts that only briefly mentioned dangerous spells or magical creations, leaving the details intentionally vague.
Hogwarts' Restricted Section, however, often held the answers for those willing to search.
That said, there were gaps even here.
For example, in Magical Philosophy: Volume III by Tywin, William had once found a reference to Horcruxes but had never been able to locate detailed instructions.
All he found was a passing mention in Moste Potente Potions: "This, the most wicked of magical inventions, shall not be discussed or instructed herein."
It was maddeningly frustrating, like Fermat's infamous marginal note that went like, "I have discovered a truly marvelous proof of this proposition, which this margin is too narrow to contain."
Why mention it if you're not going to explain it? It was utterly infuriating!
"So it takes seven years just to create one basilisk egg? that explains why basilisks are so rare," Cedric said, shaking his head.
William added, "Actually, the basilisk egg doesn't only produce basilisks.
"If it's hatched by a poisonous snake instead of a toad, it creates a Cockatrice."
The Cockatrice was similar to the basilisk but had wings and a rooster's head.
Like basilisks, Cockatrices were incredibly dangerous. In 1792, the Triwizard Tournament had tasked champions with dealing with one, resulting in injuries to all three headmasters and numerous student casualties.
The tournament was discontinued after that.
As the group chatted, they finally reached the end of the corridor, where they found a broken wall.
Peering through, they saw what lay beyond.
"This is... Hogwarts' sewage system," George exclaimed.
"The basilisk must have been moving through the pipes, which is why no one could find it," Fred deduced.
It all made sense now. The basilisk could access the Black Lake through the pipes and enter the Quidditch pitch through a one-way valve.
William recalled a detail from a blueprint of Hogwarts that Dumbledore had shown him:
In the 18th century, Corvinus Gaunt had overseen the construction of Hogwarts' sewer system.
The Gaunt family, being descendants of Slytherin, likely knew of the Chamber and deliberately designed the sewer system to conceal the basilisk, preventing others from finding it.
"This place is so intricate. Even if we investigate thoroughly, it'll take a long time and we might still get lost," Cedric said.
Hogwarts' extensive pipe network made navigating without getting lost a difficult task.
"No worries. We've got this," Fred said with a grin, pulling out his prized possession.
A Niffler.
Indeed, the Niffler was always the MVP!