Looks like I'll need to pay more attention to the professors' mental states…
Mulling this over quietly, Albus Dumbledore led Severus Snape as they flickered out of the flames and entered a dim, damp, and unimaginably vast space.
What lay before them was a bizarre sight.
They stood on the shore of a black lake. Its surface stretched endlessly into the darkness, so wide that even discerning the opposite bank was difficult. The cavern itself was even more staggering—looking up, the ceiling was nowhere to be seen. If someone were to dot the walls with a few stars, one might genuinely mistake it for the depths of outer space.
Far away, seemingly at the center of the lake, a hazy green glow flickered faintly, reflected in the deathly still waters below. Aside from that, there was nothing but darkness so thick it seemed almost tangible.
"He really knows how to pick a place," Dumbledore said, his gaze seeming to pierce the curtain of darkness, half sighing, half admiring. "Who would have thought that such an enormous natural cavern could be hidden beneath London?"
Perched on his shoulder, Fawkes let out a soft cry in agreement.
"But it's clearly been altered," Snape said, having completely forgotten the earlier awkwardness, his expression severe to the point of intimidation. "Just standing here, I can already sense over a dozen traces of Dark Magic. He placed terrifying protections on his Horcrux."
"History has taught us again and again that pure defense never guarantees invincibility," Dumbledore replied lightly.
He then drew his old wand once more, raising it and moving it slowly as he closed his eyes, carefully attuning his senses. Seeing this, Snape simply lowered his own wand—he was well aware of the gap between himself and Dumbledore when it came to spellwork.
"There's something beneath the lake," Dumbledore said after a moment, opening his eyes again. "Not particularly powerful, but numerous, and dormant… likely bound Dark creatures, or Dark Magic constructs. Entering the water recklessly would invite an ambush."
A flicker of blue flame sparked at the tip of Snape's wand as he looked to Dumbledore questioningly.
"It's possible—but unnecessary," Dumbledore shook his head. "The Horcrux isn't at the bottom. There are no further magical traces down there. I believe it's been placed on the island at the center of the lake—especially since I've found this."
He closed his hand as if grasping something invisible, then slowly moved closer to the shore. With his other hand, he tapped his clenched fist lightly with the tip of his wand.
At once, a thick chain of greenish bronze appeared out of thin air in Dumbledore's grasp. It slithered like a snake through his hand, clattering onto the ground in a coiling heap, the metallic sounds echoing against the cavern walls. The chain dragged something up from the pitch-black depths of the lake—
The prow of a small boat emerged ghostlike from the water, glowing with the same eerie green as the chain, drifting toward the shore where Dumbledore and Snape stood, barely disturbing the surface.
"A trap?" Snape frowned. "There doesn't seem to be any sign of danger on it…"
"Indeed. It's likely Voldemort's own back door," Dumbledore said calmly. "But this confirms there are no other unknown dangers in the lake. Take my arm, Severus."
With a roaring burst of flame, Dumbledore and Snape vanished once more, reappearing directly on the island at the center of the lake.
"…Are we really not going to follow the procedure?" Snape released Dumbledore's arm, his expression strange. "Did it never occur to you that there might be detection magic on this island? If someone arrives without the boat docking first, it could trigger a powerful trap."
"Thank you for the reminder, Severus—you're more thorough than I am," Dumbledore said after a brief pause. "It's fortunate Voldemort didn't hire you as a consultant when building this place. Otherwise, I might be paying the price right now. He didn't think along those lines."
"…"
Only then did they properly examine the island up close.
It resembled a massive slab of flat black stone, roughly the size of a classroom. It was completely bare—save for the source of the green light. Now that they were closer, the glow was much brighter. It emanated from a stone basin resembling a Pensieve, raised on a pedestal to about table height.
The basin was filled to the brim with a vivid emerald liquid, quietly emitting a shimmering phosphorescence.
"So this is the final line of defense," Dumbledore said, gesturing toward the basin. "By his standards, it should also be the strongest—and the hardest to break. Your area of expertise, Severus."
"I know."
Snape nodded and once again drew his wand, focusing intently on examining the liquid. After a while, he pulled out a variety of multicolored reagents, applying them to the green liquid or the surface of the basin.
"It's troublesome," he concluded without much concern—after all, everything that had truly worried him so far had been casually resolved by the old man beside him, and this was unlikely to be different.
"This is a compound of potion, curse, and ritual magic. It's so resilient it's practically indestructible. I can't find any way to break it by force."
"I'm now convinced the Horcrux lies at the bottom of this liquid. This substance cannot be touched. It can't be parted, scooped out, or drained. It can't be vanished, transfigured, or altered by any magical means. The basin and pedestal beneath it are also nearly indestructible. And the only way to make the liquid disappear is—"
He produced an empty measuring cup and effortlessly ladled out a cupful of the liquid.
"To drink it."
"An appalling sense of humor," Dumbledore remarked.
"Indeed. And a lack of imagination," Snape agreed.
Holding the cup with practiced elegance, Snape conjured a snake with his wand, ordered it to open its mouth wide, and poured the liquid in.
Bang!
The instant the liquid touched the snake, it was annihilated into nothingness. And the potion—having destroyed the snake—vanished from midair and returned to the basin in the same heartbeat.
"…Hmm?"
Snape frowned sharply. "What's going on? Is there a component I failed to detect…?"
He began pulling item after item from his pockets, rapidly assembling them. Before long, several large instruments surrounded the basin, nearly filling the entire island. Even Dumbledore couldn't help a twitch at the corner of his eye. Snape stood outside the apparatus, wand in hand, chanting spells with intense concentration, beads of sweat gradually forming on his brow.
The examination lasted nearly twenty minutes.
When Snape finally lifted his head again, Dumbledore was startled by the look on his face—a ghastly pallor, a mix of shock and frustration.
"…Soul," Snape said through clenched teeth. "The principles behind this potion involve the essence of the soul. Only a true, living being—one with a soul—can drink it completely. There are no tricks that can bypass it."
(End of Chapter)