Professor Dumbledore did not just summon the staff. He moved with a speed and decisiveness that showed the gravity with which he took Ariana's plan. Within the hour, Hogwarts was a fortress on high alert. An official announcement, delivered by Dumbledore's magically amplified voice, echoed through the halls, ordering all students to return to their house common rooms immediately and remain there until further notice. Prefects patrolled the corridors, their faces grim, ensuring the lockdown was absolute.
But Dumbledore's preparations went further. As Ariana, Harry, Ron, and Hermione waited in his office, they saw a succession of visitors arrive via the Floo network. First was Professor McGonagall, her face set like stone, her wand already in her hand. Then came Professor Snape, his expression a mask of cold fury, though whether it was directed at the situation or at them was unclear.
Then, a formidable-looking witch with a stern jaw and a monocle stepped out of the green flames, her aura of crisp, no-nonsense authority immediately filling the room.
"Albus," she said, her voice sharp as steel. "Your message said it was a matter of national magical security."
"It is, Amelia," Dumbledore confirmed gravely. "Thank you for coming on such short notice."
This was Amelia Bones, the Head of the Department of Magical Law Enforcement. And behind her came two more figures, clad in the dark, practical robes of on-duty Aurors.
Ron and Hermione stared, utterly awestruck. This was no longer a school matter. This was a full blown Ministry operation. Ariana, however, simply nodded in quiet approval. Dumbledore had not just accepted her plan; he had escalated it correctly. This was the proper response to a Class-X magical beast loose in a school full of children.
"Miss Dumbledore," Dumbledore said, turning to her. "Your hypothesis has led us here. Please, brief Director Bones on the situation."
Calmly and concisely, Ariana laid out the entire theory: the Basilisk, the petrifications via reflection, Harry's Parseltongue ability, the voice in the walls, and the suspected location of the entrance in Moaning Myrtle's bathroom. She presented it not as a story, but as an intelligence briefing, her logic clean and irrefutable.
Amelia Bones listened intently, her monocle fixed on Ariana, her expression shifting from skepticism to grim belief. "A Basilisk," she breathed when Ariana was finished. "In Hogwarts. And you, a second-year, deduced this?"
"The data was available," Ariana replied simply. "I merely connected it."
"Very well," Bones declared, her voice now hard as iron. "The castle is secure. Professor
Dumbledore, lead the way. Potter, you'll be with us. Your ability is the key."
The group that descended to the second-floor lavatory was a force to be reckoned with.
Dumbledore and Amelia Bones led the way, flanked by the two Aurors. McGonagall and Snape followed, their wands drawn. And in the center of this protective diamond of immense magical power walked the four students.
They found Moaning Myrtle floating miserably over her usual toilet. "Oh, it's you," she said, seeing Harry. "What do you want?"
"We need to find the entrance, Myrtle," Harry said, his voice echoing strangely in the silent, tense room.
Dumbledore gently pointed to a sink tap that Harry had never noticed before. It was old and copper, and etched into its side was a tiny, almost invisible serpent. "Harry," he said softly. "If you would."
Harry focused on the carving. He imagined it was a real snake and hissed, "Open up."
The Parseltongue command worked just as Ariana had predicted. The copper tap glowed with a green light, and the entire sink began to sink into the floor, revealing a large, dark, gaping pipe leading down into utter blackness.
"Remarkable," Amelia Bones murmured.
"There are no stairs," Ron said, peering into the dark hole.
Ariana turned to Harry. "The creator would not have built an entrance he could not use.
Parseltongue is the key not just to the lock, but to the entire mechanism. The control is verbal. Instruct it."
Harry, understanding, faced the dark opening again and hissed, "Stairs."
With a deep, grinding groan of ancient stone, a spiral staircase materialized out of the damp walls of the pipe, descending into the darkness below.
"Excellent thinking, Miss Dumbledore," Dumbledore said with an approving smile.
"Aurors, take point. Harry, you will stay in the center of the formation at all times. The rest of you, wands at the ready."
They descended into the depths of the castle, their footsteps echoing in the oppressive silence. The tunnel led them through a series of chambers littered with the bones of small animals, each door opening only to Harry's sibilant commands. Finally, they reached a solid wall carved with two intertwined serpents with emeralds for eyes.
"This is it," Dumbledore said, his voice low. "The final gate."
Harry spoke the command to open, and the stone serpents parted, the wall sliding away to reveal the main Chamber. It was a long, cavernous room lined with towering pillars carved like snakes. A sickly green light filled the space, emanating from an unseen source. At the far end of the Chamber, a colossal statue of Salazar Slytherin rose to the ceiling, his face ancient and monkey-like.
But it was what lay coiled at the base of the statue that made them all freeze.
It was a snake. A truly massive one, thicker than a tree trunk and easily twenty feet long. But it was not a Basilisk. Its scales were a beautiful, iridescent pattern of green and brown, and its eyes, large and intelligent, were not the killing yellow of the King of Serpents.
The snake lifted its great head, its forked tongue flicking out, and a voice echoed in Ariana's and Harry's minds, clear as a bell.
"So, the little speaker returns. And he has brought the old man."
Dumbledore stepped forward, his expression one of profound, sorrowful recognition. "Nagini," he said, his voice filled with a weary sadness. "After all these years. I had thought you long gone."
"I go where my master wills me," Nagini hissed in reply, her gaze flicking past Dumbledore to settle on Ariana. "And I see… a familiar scent. The blood of my own line. How strange that you should stand with him."
Ariana's question—the one that had tormented her since Halloween—was answered in that single, chilling moment. It hadn't been the diary. It had been Nagini. Voldemort's most loyal servant, the Maledictus, his future Horcrux. Ariana's presence last year for the fight must have deviated Voldemort's actions, and Voldemort's wraith-like spirit, upon escaping Hogwarts, had been able to reawaken her and command her to open the Chamber from the inside.
"It was you," Ariana said aloud, her voice calm despite the revelation. "You opened the Chamber on his command."
"The Master's will must be done," Nagini hissed. Her great head turned towards the gaping mouth of the Slytherin statue. She let out a single, long, commanding hiss in Parseltongue, a command far more complex and powerful than any Harry could produce.
"The King of Slytherin awakes! Defend
the sacred Chamber! Kill the intruders!"
From the black depths of the statue's mouth, something vast began to stir. A sound of immense slithering, of scales the size of dinner plates scraping against ancient stone, echoed through the chamber.
"The Basilisk comes!" Dumbledore roared. "Shield your eyes! Do not look at it directly!"
Nagini gave a final, triumphant hiss and slithered away, disappearing into a dark tunnel at the side of the chamber, her mission complete. She had summoned the beast.
The professors and Aurors immediately raised their wands, preparing for a battle against a creature none of them could afford to look at. The endgame had been forced, the players were all on the board, and from the darkness, the true monster of the Chamber of Secrets was finally coming out to play.