Although the area revealed by the puzzle greatly narrowed down their search, when they projected it onto the actual map to scale, a wave of frustration inevitably crept into their hearts.
The region was still far too large—spanning several blocks and valleys, with complex terrain, abandoned factories, wild hills, and even traces of vast underground structures. Even worse, the entire zone was now under tight control by Eryx's patrol units, who left no gaps unguarded.
"This area… there's no way we can sweep it manually," Elias said, staring at the map with a helpless tone. "Especially without any official authority."
Marcellus clenched his fist. He knew exactly what that meant. The map had pointed them in the right direction, but it couldn't give them a precise location. With a sigh, he muttered, "Looks like we'll need Edgar to pull Eryx out—otherwise, we won't even get a chance to act."
The mood grew heavy—until Livia suddenly slapped her forehead, her eyes lighting up.
"Wait, I just remembered something. We might have another lead."
Both men turned toward her at once.
Livia spoke rapidly. "Back when I was investigating, I accidentally heard a 'summoning' voice—and it came from a water pipe underground. I had Adrian look into the city's water and sewer system to see if there were any anomalies."
Without waiting for a response, she pulled out her phone and dialed Adrian. The call connected after just two rings.
"Adrian, how's your end coming along?"
"Oh, I've just about finished mapping the water lines… but honestly, I still don't know where that thing is."
"Never mind that. Bring the maps to the hospital immediately. We've made progress—this could be the final piece of the puzzle."
A brief silence on the other end, then Adrian's voice came back, quick and resolute: "Got it. I'll be there in thirty minutes."
—
Elsewhere, Edgar sat alone in his study, staring silently through the massive floor-to-ceiling window at the thunderclouds gathering over the city.
He didn't know what Marcellus was thinking right now, nor was he sure what exactly his daughter had uncovered. A master of maneuvering behind the scenes, he was starting to sense that the game was slipping out of his control.
But one thing he had always been certain of—what he wanted. His time was running out. The Grail was his only hope.
He turned his head slowly, eyes settling on a tall cabinet in the corner, draped with a cloth of fine brocade. Rising to his feet, he walked over and gently lifted the cover.
Inside was a small, inconspicuous fragment—a broken piece of ancient metal, with faint, unrecognizable markings etched along its edge. He had never told anyone about it, never tried to match it with any known records. Because he already knew—this shard was a piece of the Holy Grail.
He stared at the fragment, a storm of emotions flickering in his eyes: doubt, excitement, and… the desperate resolve of one with nothing left to lose.
—
Back at the hospital, Adrian finally arrived in a rush, a sheen of sweat still clinging to his face. Livia grabbed him the moment he stepped through the door.
"Don't talk. Just hand over the maps."
Adrian unfolded several printed schematics while explaining, "I compiled the entire city's and outskirts' still-active underground water networks. I ruled out abandoned zones and small pipelines that are too close to the surface or structurally unstable."
"If the 'Grail' really is hidden somewhere down there, it'll need both space and stability. If it were too close to the surface, the energy fluctuations would've already affected the area above."
He pointed to various marked spots on the maps. "I also factored in fluid dynamics, analyzing flow patterns to find the places least likely to be noticed. Red markers show the highest anomaly likelihood. Yellow, secondary."
Marcellus, Livia, and Elias immediately began comparing Adrian's water system map with the earlier puzzle diagram and the textual map from the Grail document. Livia's finger traced along the layers—and then paused, unmoving.
"…Look here."
The three of them held their breath and leaned in.
At the intersection of the three overlaid maps, a red marker lay directly over the densest region of their combined data. It pointed to an old well—once part of the castle's water supply system—later extended into the northern part of the city's underground, just beyond the northern edge of Marcellus's castle grounds.
Elias read the name aloud in a hushed voice: "Asta Well… I feel like I've heard that name before."
Livia's expression darkened slightly. "It's one of the old wells from years ago. They say it led to an underground passage, but it was sealed off later."
Adrian slapped the table, eyes gleaming. "Then we have to check this place out!"
The three exchanged glances—and at that moment, a shared certainty swept over them: they had finally found the true entry point to the Holy Grail.
But they also knew—the area was still under Eryx's tightest watch. To get anywhere near it, there was only one way: Edgar would have to make good on his promise to pull Eryx back.