Breathing and swimming freely underwater was a surreal experience. Even so, as the natural light faded and the crushing silence of the depths set in, Neville and Wendy's initial adrenaline quickly wore off. Fortunately, Richie stayed at the front of the formation, keeping his wand illuminated with the Lumos charm to guide the way. It grounded them and kept the panic at bay.
Soon, Richie stopped his descent. Wendy and Neville halted as well, hovering weightlessly beside him. According to their pre-dive strategy, this run was strictly for reconnaissance.
The third riddle was highly poetic:
> The mirror of the inverted starry river, chanting a silent, ancient ode.
> When the strings are plucked, the starlight shall dance in a celestial gown.
They had broken the riddle down piece by piece before the dive.
The mirror of the inverted starry river: This likely referred to the surface of the Black Lake on a perfectly clear night, acting as a mirror to the night sky.
Chanting a silent, ancient ode: This implied there was either an entity living in the lake, or the lake itself "sang" under the stars.
When the strings are plucked: This meant that playing a stringed instrument would cause the starlight reflecting on the water to physically shift and point them toward the answer.
But what exactly in the Black Lake was ancient and capable of singing? Was it a magical creature, or just a unique geological formation? Like wind howling through a canyon, maybe the underwater currents moving through specific rock structures created a resonance—a "silent, ancient ode."
They had scoured the library for clues and finally found a rough overview of the Black Lake in Hogwarts: A History. The lake wasn't just a body of water; it was a massive, thriving habitat for magical creatures. Merpeople, the Giant Squid, Grindylows... they had lived down here since the castle was built.
After being "persuaded" by the four Founders, the creatures agreed to stay in the depths and not attack the surface or the students on the shore. Slytherin had even built his house's common room deep beneath the water. But despite the ancient truce, plenty of students had still drowned down here over the centuries.
Because of that brutal reality, Richie had explicitly scheduled the dive for broad daylight.
First, according to the texts, most of the lake's dangerous creatures were highly sensitive to light and would be asleep in their dens during the day. Second, as humans, losing their vision in a high-risk aquatic environment would massively spike the danger level.
This daytime dive was purely to map out underwater geological structures. Seeking out magical beasts was way too risky, and Richie had zero intention of doing so right now. If he were alone, he might have considered it. But after the near-fatal ambush by the animated knight during their Clock Tower expedition, he deeply regretted bringing his friends into the line of fire. He wasn't going to let that happen again. Today was strictly a sightseeing tour.
Richie waved his wand, signaling them to spread out. Neville and Wendy immediately drew their wands and cast their own Lumos charms.
They had established clear visual comms beforehand:
Steady Light: Standard positioning.
One Flash: Found something.
Two Flashes: Surface immediately.
Tug the Rope: Extreme danger.
Given their magical proficiency, holding a simple lighting charm for an hour was effortless, making it the perfect underwater communication system. The three of them fanned out, maintaining a safe distance.
Richie looked down. They were currently hovering at about three-quarters of the way to the bottom. Even from this height, the topography was relatively clear. Just as Richie had pictured, the lake floor was a massive, rugged network of trenches and ravines. It looked like an underwater canyon choked with thick beds of kelp. Streams of tiny bubbles floated up from the weeds—either oxygenation from the plants or something hiding inside them. Further out, towering stone pillars jutted from the lakebed, completely covered in thick green flora that swayed in the current like massive tentacles.
Keeping one eye on Neville and Wendy's distance, Richie swam forward to map the terrain.
But the second he passed over the dense kelp beds, several pairs of glowing eyes snapped open in the dark, locking dead onto his back.
---
The Black Lake was deceptively massive. After swimming for nearly an hour, they hadn't even scratched the surface of the mapped area.
The dive wasn't without its hiccups, either. Neville nearly had a heart attack when he mistook an old boot for an ambushing Merperson, and Wendy swam out a bit too far, yanking the safety line and causing a brief panic.
Still, the recon was successful. They spotted a hollowed-out mountain structure, the faint, distant outlines of the Merperson village, and several stone pillars carved with bizarre, ancient runes.
As their time limit approached without any actual disasters, Richie let out a mental sigh of relief. He flashed his wand twice. Neville and Wendy immediately grouped up on his position, and the three of them kicked upward.
The water grew brighter and warmer until they finally breached the surface.
"Over here!" Seamus practically jumped up and down on the shore, frantically waving his arms the second they popped up.
Relieved, they swam to the bank and hauled themselves out of the water. Almost instantly, their gills sealed up, and the webbing between their fingers and toes melted away.
"Oh man, it is absolutely incredible down there!" Neville immediately started hyping up the dive to Seamus. "It's so quiet, and there's just so much..."
Seamus listened, his face twisting with pure envy. "Merlin, that sounds amazing. Did you guys find the answer?"
Neville shook his head. "No. The lake is way too huge."
Richie shook the water out of his hair and cast a quick, standard drying charm to pull the moisture out of his clothes.
"Don't let Neville sell you on how peaceful it is down there, Seamus," Richie interrupted, noticing the Gryffindor looking a little too eager to try it himself. "The most beautiful things are usually the most dangerous. Don't forget the warnings in the history books. People have died down there."
Hearing Richie drop the reality check, Seamus, Neville, and Wendy all visibly shivered.
"Richie, come on, we literally just got out of the water!" Neville complained, suddenly remembering the terrifying "ambush boot" and feeling a delayed wave of dread.
"I'm just saying, we need to respect the lake," Richie said, seamlessly shifting gears. "You guys remember the terrain we saw, right? Let's sketch it all out while it's fresh. Then we can actually start researching it."
Neville looked back at the glittering surface of the Black Lake, swallowed hard, and gave a slow, hesitant nod.