Chapter 175: "The Marauder and the Chamber of Secrets"

As evening fell over Hogwarts, Harry learned that Sirius had arrived at the school. He was leading the first group of Aurors, not to confront the basilisk, but to ensure the safe evacuation of students to the Hogwarts Express. Eager to see his godfather, Harry sought him out.

Sirius greeted Harry with a mixture of relief and concern. "Harry, thank Merlin you're alright. Amelia sent me personally to make sure you and Susan were safe. What in Godric's name is going on here? Dumbledore's been tight-lipped, only mentioning a basilisk attack."

Harry recounted the story he'd told the professors, watching Sirius's face grow increasingly worried. When he finished, Sirius ran a hand through his hair, a habit Harry recognized as a sign of stress.

"Merlin's beard, Harry. Taking on a basilisk... I'm proud of your courage, but you could have been killed!" The old Gryffindor in Sirius couldn't help but admire his godson's bravery, even as the concerned guardian in him fretted.

Sirius cast a quick Muffliato charm and leaned in closer. "Now, what aren't you telling me? I know that look in your eye, pup. You're holding something back."

Harry glanced around, then led Sirius to an empty classroom. After casting additional privacy charms, he took a deep breath. "You're right, Sirius. There's a lot more going on."

Over the next few minutes, Harry laid out everything to Sirius: his investigations into the attack, suspicions about Evelyn Rosier, the signs of possession he'd observed, and his theory about Voldemort's Horcrux behind everything. Sirius listened, his face growing grimmer with each revelation.

"Another Horcrux? How many of those monstrosities has that mad guy made and how did such a seriously dark object get through Hogwarts wards? And you think Voldemort's trying to resurrect himself?"

Harry nodded solemnly. "I had planned to deal with the Hircrux and the basilisk tomorrow when the school was empty, but with you here, we might be able to end this tonight."

Sirius straightened, his eyes gleaming with determination. "What do you need me to do?"

For the next thirty minutes, Harry outlined his plan in detail, explaining the Chamber's location, how to access it, and his now modified plans to save Evelyn and destroy the Horcrux. Sirius listened intently, occasionally asking for clarification but mostly marveling at his godson's knowledge of everything surrounding the Heir and the Chamber of Secrets. He loved the plan Harry had come up with to deal with everything.

---

As night fell and the castle grew quiet, Sirius made his way to Moaning Myrtle's bathroom. The corridors were eerily silent, with only the occasional whisper of a ghost or creak of ancient stone breaking the stillness. At the sink Harry had described, a soft hiss revealed the entrance to the Chamber.

Without hesitation, Sirius plunged into the dark slide, feeling a mix of exhilaration and trepidation as he descended into the bowels of Hogwarts. Behind him, the entrance sealed itself with another hiss.

As he navigated the narrow, damp tunnels, Sirius couldn't help but be impressed by the intricate network hidden beneath the school. "Slytherin, you crafty old snake," he muttered, noting how the pipes seemed designed for more than just plumbing. They were perfect pathways for a giant serpent.

Each obstacle Harry had warned him about opened at the sound of that mysterious hiss, leading Sirius deeper into the Chamber. Finally, he emerged into the vast hall Harry had described. The towering pillars and the enormous statue of Salazar Slytherin loomed before him.

"Blimey, Salazar," Sirius chuckled nervously, "Godric was definitely the better-looking founder."

His humor faded as he spotted a small figure huddled at the base of the statue. Evelyn Rosier lay there, pale and still, but mercifully alive. Sirius approached cautiously, wand at the ready.

Sirius called out, "Miss. Rosier? Are you alright? I'm here to take you to safety."

The girl turned to Sirius, but he immediately sensed something was amiss. Her eyes were glazed, her movements unnatural. She was clearly possessed, though there was no visible specter of Tom Riddle. The possession hadn't progressed far enough for that.

The voice that came from Evelyn's mouth was not her own. It was cold, calculating, and unmistakably male. "Who are you? How did you get here? Only a Parselmouth could reach this place, and the only one I know of is Charles Potter. I expected him or perhaps that meddlesome Dumbledore."

Sirius smirked, falling easily into the role Harry had prepared him for. "Shows how little you know. Many old families, like the Blacks, have had this talent. We just keep it quiet. Now, who might you be? Some dusty old ghost with delusions of grandeur?"

The possessed girl's face contorted with anger. "I am Lord Voldemort," the voice hissed.

Sirius gasped dramatically, channeling his inner thespian. "No! It can't be! The dreaded You-Know-Who, possessing a schoolgirl? How the mighty have fallen! Who are you really, old pervert?"

The possessed heir bristled. "I am not an old pervert. I am Tom Riddle, a young Slytherin prefect."

Sirius raised an eyebrow, his voice dripping with sarcasm. "There you go lying again. First, you said you were Voldemort, and now you say you're Tom Riddle. Make up your mind, old chap."

"I am both," the possessed heir snarled, and then proceeded to demonstrate how the name 'Voldemort' was an anagram of 'Tom Marvolo Riddle'.

Sirius collapsed to the floor in a fit of exaggerated laughter. "That's how the name Voldemort came about? It's too funny! I can't wait to tell all the pureblood Death Eaters that their lord was playing word games. What's next, a secret handshake?"

"You dare mock me?" the possessed heir snarled with her wand now pointed towards SIrius. "I am the greatest sorcerer in the world! I am going to torture you!"

"Oh, I don't know about that," Sirius drawled. "I've heard Dumbledore can do a mean tap dance. Can you top that, Voldy?"

Just when a furious Riddle was going to cast the killing curse on Sirius, a bright green light flashed through the chamber, striking the possessed Evelyn and sending her wand flying. Before Tom Riddle could react, Sirius's voice rang out, "Petrificus Totalus!" The girl's body went rigid, frozen in place.

The soul of Tom Riddle was bewildered. One moment he was seething with anger, the next he found himself wandless and immobilized, defeated so easily. He, Lord Voldemort, outsmarted by this puny adversary.

As if things couldn't get worse for the Dark Lord, a shimmering ward suddenly sprang up around them, cutting off any commands of Tom Riddle from reaching the basilisk hidden behind the statue.

It was then that Harry pulled off his invisibility cloak, grinning at his godfather. "Nice work, Padfoot. You should consider a career in theater."

Sirius chuckled, relief was evident in his voice. "And you, pup, could give Mad-Eye a run for his money in the stealth department."

Sirius then began searching Evelyn's robes for the Horcrux, while Tom Riddle futilely tried to resist, unable to move. Finally, Sirius extracted the diary, causing a flicker of fear in Evelyn's possessed eyes.

Handing the diary to Harry, Sirius said, "I've had my turn, now it's yours. Destroy it and make this annoying git disappear."

"Very well," Harry replied, he had not told him the fact that he had already destroyed many Horcruxes already. He couldn't pass up the opportunity for more soul reinforcement and strengthening.

Tom Riddle, realizing what was about to happen, was terrified. In desperation, he tried to command the basilisk in Parseltongue to rescue him and kill these wizards. But thanks to Harry's ward, no sound could reach the snake.

Harry raised his wand and cast the Horcrux-destroying spell at the diary. A brilliant white light erupted from his wand, engulfing the diary. Tom Riddle screamed in agony, but within seconds, he was no more. The white light rebounded and struck Harry, suffusing him with power.

"How do you feel? Any stronger?" Sirius asked, watching his godson closely.

Harry paused, assessing the changes within him. "I feel something. Not entirely sure what." This time around destroying the Horcrux, Harry did notice a significant improvement. Given that the diary was Voldemort's first Horcrux and contained the largest chunk of his soul, it provided Harry with the most substantial boost yet. He could already sense his mind becoming clearer and his magic growing stronger.

Sirius nodded. "Good. You'll need that strength when this git finally resurrects himself. Who knows how many soul anchors this monster had created for himself."

"We'll destroy them all eventually," Harry assured him. "Thanks to you, this was much easier than the battle I'd planned."

They shared a moment of triumph, savoring their well-executed plan. Without a single spell cast in battle, they had saved Evelyn and destroyed the Horcrux. 

As the echoes of their victory faded, Harry and Sirius turned their attention to the unconscious Evelyn. With a gentle levitation charm, they carefully lifted her off the damp chamber floor.

"Let's get her out of here," Sirius said, his voice low. "We'll need to have her checked over by Madam Pomfrey."

As they made their way back through the winding tunnels, Evelyn's limp form floating between them, Sirius spoke again. "We'll come back with reinforcements, Harry. That basilisk needs to be dealt with soon. It's a hidden danger for the school."

Harry nodded and followed Sirius quietly. He had his own plans for the basilisk, but Sirius didn't need to know that.