After a minute, the loud sounds of rock crashing against rock ceased, and Harry tentatively moved his arms away from his head.
"Harry?!" Cassandra shouted, her voice quieted by the thick wall of rock between him and the girls.
"I'm here!" Harry called back, "Is everyone alright on that side?"
"Yeah, we're all good. Well, Lockhart's still out from his own Memory Charm." Gabrielle replied, her voice raised as well.
"Alright. I'm going to keep going!" Harry shouted.
"Wait, hang on!" Cassandra called.
"No, I can't. This rock wall is too thick. I've got this." Harry said, trying to sound more confident than he felt.
There was a pause.
"Damn it, Harry. You better come back alive!" Cassandra ordered.
"Yes, ma'am." Harry said, and turned away from the rock wall, looking down the dark tunnel.
"Lumos." Harry said, raising his wand.
Onwards he trooped, into the blackness, his only light the glow of his wand.
The tunnel seemed like it lasted a long time, but finally Harry emerged into the Chamber itself.
The room was vast, a long rectangular hall with eerie green lighting. Great sculptures of serpent heads lined the walls, each head about the size of a Muggle car, maybe a little larger.
At the end of the chamber was the biggest serpent head of them all, this one the size of a house. A glance over his shoulder showed an identical serpent head that he had emerged from.
At the far end of the hall, a few feet before the serpent head, a figure lay on the dark green tiled floor, a figure with bright ginger hair.
Harry raced forwards, dropping to his knees to bend over Ginny Weasley. Her eyes were closed, and Harry leaned down to press his ear to her chest, listening for a heartbeat while studiously ignoring her perky breasts pressing against his cheek.
Her heart was beating, but it was slow and faint.
"She won't wake." a voice said, and Harry leaped to his feet, wand raised.
A tall, dark-haired boy in maybe his fifth year was standing there.
"Why not? Who are you?" Harry demanded.
"I'm Tom Marvolo Riddle. I'm the one who who closed the Chamber fifty years ago." the boy said, raising his hands. Harry's wand point dipped a little, but remained aloft.
"How are you so young?" Harry asked suspiciously. Riddle gestured at an item on the floor, and Harry glanced down at it. It was the black diary with T M Riddle on the front. Had Ginny been the one to rifle through his stuff? Had she broken in to get the diary?
"I preserved an echo of myself in this diary, to help, in case the Chamber ever opened again." Riddle explained.
"Didn't you seal the Chamber?" Harry asked.
"I did the best I could, but it was created by a Founder. I didn't have a chance of sealing it up." Riddle explained, his hands still raised.
Harry nodded, dropping his accusing wand arm.
"Alright. Help me get Ginny out of here before that basilisk comes out. Why did it take her anyway?" Harry asked, moving to lift Ginny up. He held the limp first year girl in his arms, and looked at Riddle.
"The basilisk didn't take her. She came down here willingly." Riddle said, coming up alongside Harry.
"Why would she do that?" Harry asked.
"Because I told her to." Riddle said, and quickly snatched Harry's wand from his hand, which he couldn't stop because of Ginny gathered in his arms.
Harry gently lowered Ginny to the ground, glaring at Riddle.
"You're not here to help." Harry said. Riddle laughed, cold and cruel and sadistic.
"No, I am most certainly not." Riddle said, and using Harry's wand, he began to trace letters into the air.
"I am indeed an echo, but I am not here to keep the Chamber closed. I came here to ensure it opened again." Riddle said.
"How?" Harry demanded, playing for time, and hoping a basilisk could eat an echo, if the giant snake showed up.
"I possessed young Ginny Weasley. All year, I've made her do my bidding. She killed all the chickens at Hogwarts, and used their blood to write messages on the wall. Using her body as a vessel, I released the snake into the school time and time again, instructing it to go after Mudbloods. The snake didn't want to do my bidding, of course, but as a Parselmouth, it had no choice. The basilisk may be Queen of Serpents, but I am her master." Riddle sneered.
"The snake got a pureblood. If you only wanted Mudbloods, why did a pureblood get Petrified?" Harry demanded.
"Those who associate with Mudbloods are as worthless to me as the Mudbloods themselves." Riddle said dismissively, and stepped back, revealing the phrase TOM MARVOLO RIDDLE burning in the air in crudely drawn letters.
Riddle flicked his wand, and the burning letters rearranged themselves.
I AM LORD VOLDEMORT
Harry was so stunned that a snarky comment just fell out of him.
"And to think, you could have done Lord Ear Mold Vomit." Harry said. Riddle growled.
"What sort of idiot makes his code name an anagram of his name? What should my code name be, Parry Hotter?" Harry laughed.
In truth, he was unnerved. But he wouldn't show weakness to Voldemort. He'd beaten him twice, he could do it again.
Riddle raised his hands above his head and shouted in Parseltongue.
"COME TO ME!" Riddle roared, and from the great serpent's mouth slithered the basilisk. A massive, terrifying fifty-foot basilisk with fangs the length of Harry's forearm, to be exact.
"Fuck." Harry grimaced. This was the worst case scenario. Riddle was controlling the damned thing.
A thought occurred to Harry. During his bad guy monologue, Riddle had said that the basilisk had to obey him, because he was a Parselmouth.
Would it have to obey Harry?
A risky plan began forming, but it required getting the basilisk away from Riddle, to minimize the possibility of Riddle overruling Harry's own Parseltongue orders.
Harry turned and dashed away, heading for a side tunnel that he'd just noticed, nestled between two of the smaller serpent heads.
The basilisk, unsurprisingly, was very fast, but Harry didn't dare look back at the basilisk, in fear of the lethal gaze.
Harry tore down the side tunnel, sensing the basilisk in hot pursuit. Harry reached the end of the tunnel fast, too fast.
"Don't kill me!" Harry shouted in Parseltongue, still facing away from the basilisk. He heard the snake pause.
"You speak the Snake Tongue?" the basilisk asked in an unmistakably female voice, a rather sultry one.
"Yes, I do. Uh, I can't imagine that the asshole out there treats you decently. Do you think you could, uh, defect to my side?" Harry asked hopefully.
"I would love to. Alas, the asshole out there is very powerful. I do not believe I would remain on your side if I faced him beside you." the basilisk replied.
"Then can you wait here?" Harry wondered.
"Gladly." the basilisk said.
"Great! Uh, I'll come back if I defeat Riddle." Harry said, "Can I turn around, or will I die from looking at you?"
"I've turned off the power in my eyes. You will be fine to turn around. Good luck, Master." the basilisk said. Despite emanating from a giant snake, the sultry female voice calling him master was a bit of a confidence booster.
Harry turned around, and met the reptilian yellow eyes of the basilisk. Nothing happened to him. He breathed out a sigh of relief, then squeezed past the stationary basilisk, racing back out of the tunnel.
He emerged out into the hall again, and saw Riddle crouched over Ginny.
"Back the fuck up." Harry growled as he approached, and Riddle turned sharply.
"How did you defeat the basilisk?" Riddle demanded.
"Talent." Harry replied. Riddle pointed Harry's wand at Harry.
"The weaker the girl gets, the stronger I become, and she is on the brink of death. When she perishes, I will become mortal again, and Lord Voldemort will rise!"
"You're insane. Do you know who I am? I'm Harry Potter, the guy you couldn't kill when I was just a year old. The guy you couldn't kill when I was twelve years old. I am always going to defeat you, Tom, and you are always going to lose!" Harry shouted, and he dived at Riddle. The two rolled across the tiles, brawling. Harry took an elbow to the face, and felt blood pouring down his nose, but he grabbed his wand and pulled it from Riddle's grasp.
Riddle dived for it, but Harry shouted a spell ("Flippendo!") and Riddle flew backwards, landing hard onto his back.
Harry fumbled to grab the diary, then pointed his wand at it.
"Reducto!" Harry shouted, expecting the diary to explode and kill the echo of Riddle, but the spell bounced off, flying past Harry's head to hit one of the serpent sculptures, which promptly exploded.
"What the-" Harry was cut off by Riddle tackling him.
"I'm harder to kill than that!" Riddle shouted, and slammed Harry's head into the tile. Then again. Then three times.
"H-Help!" Harry managed, and Riddle laughed cruelly.
"Who are you calling to?" he demanded. He brandished the diary to Harry.
"You can't destroy this. You can't destroy me!" Riddle crowed, and then the basilisk slammed into him. The great serpent's fangs snapped closed around Riddle, and one of the fangs punctured the diary.
Harry watched in amazement as a giant stab wound appeared in Riddle's chest, not from the fangs but from damage to the diary. Riddle was unharmed by any of the other fangs.
Riddle choked, and ink splattered from his mouth, not blood. Ink was also gushing from the hole in the diary.
With a loud crack, Riddle vanished, and the diary stopped bleeding ink.
"Thank you. That was… that was amazing." Harry gasped, his head throbbing, and his vision a bit shaky. The basilisk coiled up, and presented its mouth to Harry.
Understanding instantly, Harry yanked the diary off of the basilisk's fang.
"It was nothing. That ink tasted awful, but I enjoyed destroying him immensely." the basilisk confessed. Harry laughed.
"Do you have a name?" Harry inquired.
"I have not been asked that in a very long time. I was named by Salazar Slytherin, and have not heard my name spoken since he left Hogwarts. He named me Seleia." the basilisk said.
"You've been alone down here for hundreds of years? That's… that's crazy." Harry said in astonishment.
"It is. Life is miserable for the immortal. And living below ground in a bleak chamber is no life." Seleia said sadly.
"If you were smaller and less, uh, terrifying, I would offer to take you somewhere, but I don't know how to transport a massive serpent anywhere." Harry admitted.
"I do have the ability to change my shape into something more… humanoid. Yet, I hesitate. Shifting between serpent and other is difficult. Do you swear you will take me away from this subterranean hell?" Seleia asked.
"Yes. I promise you, if you turn into something more manageable to transport, I'll get you out of here." Harry swore.
Seleia reared up, and Harry watched in fascination as she began to writhe, her whole, massive serpentine body spasming as she began to shrink.
The part of her that was coiled up remained serpentine, though it shrank drastically. But her upper half began to change. Her face drew inwards, becoming human shaped. The scales along her top half began to vanish, revealing bare human skin, and arms sprouted from her torso. When her head was human shaped, pure black hair grew from it. Pointed ears grew out as well, and her face softened into beautiful female features, and though her eyes changed from reptilian to human, they remained a golden color. Large, generous breasts hung heavy and bare on her top half, and her stomach was flat and perfectly toned.
Harry's jaw hung open slightly, looking Seleia up and down. She was taller than him with her lower, still snaky half coiled up like it was. Her human half looked like a woman in her late twenties or early thirties, and was absolutely gorgeous, with her pure black hair and her pale skin.
"I am a… lamia." Seleia spoke with a heavy accent in faltering English. Her accent was incredibly unique to Harry's ears, sounding almost… Greek?
"A lamia? I've never heard of them, ah, you." Harry said.
"We are very… what is the word… rare. Salazar, he, ah, found me in Greece, and brought me… here." Seleia explained, using Parseltongue whenever she forgot the English word for it.
Ginny Weasley made a sound, then, and Harry looked at her, having almost forgotten about her lying on the tiles, too fascinated by Seleia.
"Ginny?" Harry asked softy. The pretty ginger girl's eyes fluttered open, and her brown eyes held Harry's emerald ones.
"What happened?" Ginny groaned.
"You were possessed by Voldemort. I destroyed him, with some help." Harry said, looking at Seleia.
"You cannot free me from my prison just yet, can you?" Seleia asked knowingly.
"Not just yet. I need to talk to people above ground, figure out how to get you from here to somewhere safe, like my family's estate. I promise I will free you, though." Harry admitted.
"I do not doubt you, Master. Just please… please free me as fast as you can. I long to feel the sun on my skin again." Seleia sighed, "I do not wish to frighten the girl, so I will withdraw to my lair for now. Call for me when you return."
Harry nodded, and Seleia slithered towards the serpent mouth she had emerged from when Riddle summoned her and vanished.
Harry looked down at the disoriented Ginny.
"Are you alright to walk, or do you need me to carry you?" Harry asked.
"I- I think I can walk." Ginny groaned, and rose shakily to her feet, then nearly fell. Harry caught her smoothly, and he slid an arm around her.
"Here, I'll help you walk." Harry compromised. Ginny nodded weakly.
She leaned her head on his shoulder as they walked, whimpering softly at whatever pain she was experiencing.
———
Returning to Myrtle's bathroom was a challenge, requiring Cassandra to summon broomsticks to get them back up the steep chute.
While Harry and Seleia fought Riddle, Cassandra, Gabrielle, and Astoria had been using Levitation Charms to clear out the collapsed tunnel, but they weren't finished by time Harry and Ginny reached them, so the two of them sat against the tunnel wall, Ginny fading in and out of restless sleep while Harry cradled her in his arms.
She seemed happiest that way, but from the look of her, Harry figured she would be haunted by having Voldemort possessing her for possibly the rest of her life.
Ginny was awake when the girls finally got the tunnel clear, which was good. Harry had offered repeatedly to help with clearing the tunnel, but all three girls had insisted. Harry suspected they all wished they had been able to fight with him, and were trying to make up for it now.
Harry helped Ginny to her feet and then they had flown back up to the bathroom on the brooms, and emerged to find a contingent of professors waiting for them.
Madam Pomfrey descended upon the group of them, but Cassandra, Gabrielle, and Astoria firmly refused medical attention and told her to prioritize Harry and Ginny.
Lily threw her arms tightly around Harry, and when Madam Pomfrey had ordered Harry and Ginny to the hospital wing, she had gone with them.
Professor Dumbledore then asked Cassandra to explain what had happened in the Chamber, and Cassandra, Gabrielle, and Astoria had shared the story of what they knew, and of how Lockhart had become an amnesiac, but they could not account for the events that transpired in the Chamber.
Only Harry could do that.