The access shaft opened into a small maintenance room filled with tools and spare parts. Grimble secured the hatch behind them as they removed their thermal protection gear, the cooler air of the refinery level a welcome relief after the sweltering tunnels.
"Lower maintenance level," he whispered. "Minimal staffing, especially during shift change—which is now."
Marcus consulted a schematic Steelheart had provided. "The Crystal's core chamber should be accessible through the original excavation tunnels. According to the archives, they were sealed but not destroyed."
"Where would these tunnels be located?" Alan asked, examining the schematic.
"Beneath the main refinery floor," Torbin suggested. "The Guild built upward from the original discovery site."
Grimble nodded agreement. "Old-timers speak of the 'Deep Approach'—the original path to the Crystal before the refinery was constructed. Entrance supposedly hidden in the primary support chamber."
They moved cautiously from the maintenance room into a wider corridor lined with pipes and conduits. The distant hum of the refinery's operations vibrated through the walls, growing louder as they approached a junction where their corridor met a much larger passage.
"Primary support chamber ahead," Grimble indicated. "Houses the main structural reinforcements for the refinery floor above. Also serves as equipment storage."
Lyra, who had been quiet since their ascent, suddenly raised a hand in warning. "Energy signatures approaching. Multiple sources."
They quickly retreated to an alcove containing pressure regulation equipment, concealing themselves as best they could. Moments later, a patrol of Guild security personnel passed the junction, led by an Academy enforcer in distinctive attire.
"Joint patrols," Marcus whispered once they had passed. "The Council must have approved Darkblade's request for expanded search authority."
"We need to move quickly," Grimble urged. "Support chamber will have more places to hide, and the Deep Approach entrance—if I can find it."
They waited until the patrol's footsteps faded, then hurried across the junction into the primary support chamber—an enormous space with ceiling-high stone pillars reinforced with metal bands and crystal inlays. Equipment racks and storage containers lined the walls, providing ample concealment.
"Spread out," Grimble directed. "Look for anything unusual in the floor or walls—seams that don't match, stones of different color or texture."
They separated to search different sections of the chamber, staying low and moving quietly. Alan examined the base of several support pillars, noting the intricate crystal work that seemed to serve both decorative and functional purposes.
"The crystals in these pillars," he called softly to Marcus. "They're arranged in patterns similar to the resonance diagrams from the data matrix."
Marcus joined him, studying the formations. "You're right. These aren't just structural—they're tuned to specific energy frequencies."
"Like a tuning fork," Alan suggested. "Or a resonance key."
Lyra approached, her expression thoughtful. "The entire chamber could be a harmonic structure designed to interact with the Crystal's energy patterns."
Their speculation was interrupted by Torbin's urgent whisper from across the chamber. "I found something!"
They gathered around a section of flooring where Torbin had moved aside several storage containers. The stone blocks here were subtly different—darker, with faint symbols carved into their surfaces.
"Old Guild markers," Grimble confirmed, kneeling to examine them. "Pre-standardization era. Directional indicators and warning sigils."
"Can you read them?" Alan asked.
"Partially. This indicates a 'path to the heart'—likely the Deep Approach. And these are caution markers about 'resonance disruption.'"
Marcus studied the floor section. "How do we open it? I don't see any obvious mechanism."
Grimble ran his hands over the stones, pressing various symbols in sequence. Nothing happened. "Should be a release pattern. Unless it's been permanently sealed."
Alan noticed something about the crystal inlays surrounding the marked stones—their arrangement formed a pattern similar to the equation Nexus had shown them through the data matrix.
"The crystals," he said, pointing. "They're arranged in a mathematical sequence. Like a combination lock based on harmonic principles."
He knelt beside Grimble, placing his hands on specific crystals that corresponded to key values in the equation. As he touched the third crystal, all the inlays began to glow faintly.
"It's responding," Lyra observed. "Your energy signature is activating the lock."
Alan completed the sequence, touching the crystals in the order suggested by the equation. The glow intensified, spreading to the carved symbols on the stone blocks. With a low rumbling, the section of floor began to recede, revealing a dark opening and ancient stone steps descending into darkness.
"The Deep Approach," Grimble whispered with reverence. "Unseen for centuries."
Marcus produced a light crystal, illuminating rough-hewn steps that spiraled downward. "The original excavation tunnel. From before Ironhammer's founding."
"We should hurry," Lyra urged, glancing toward the chamber entrance. "That mechanism likely triggered monitoring alerts."
They descended the ancient stairs, which showed signs of having been carved directly from the living rock of the mountain. Unlike the refined construction of Ironhammer's later passages, these walls bore the marks of primitive tools and desperate haste.
"Our ancestors were in awe when they first discovered the Crystal," Torbin explained as they descended. "The earliest records describe workers fleeing in terror, believing they had found the heart of a god."
The stairs seemed to descend forever, the air growing noticeably different—not hotter, as in the thermal tunnels, but charged with a subtle energy that made the hair on Alan's arms stand up.
"The Crystal's direct emanations," Marcus explained, noticing Alan's reaction. "Unfiltered by the Guild's containment systems."
Finally, the stairs ended at a small chamber with a single archway leading forward. Ancient symbols covered the walls—more elaborate than those on the floor above, depicting figures bowing before a crystalline structure.
"Warning glyphs," Grimble translated, studying the carvings. "Admonitions to approach with reverence and maintain harmonic balance."
Beyond the archway lay their destination—a perfectly circular chamber dominated by what could only be the Great Crystal's core. Unlike the massive formation Alan had seen in the refinery above, this was smaller but more intensely radiant, a crystalline structure about the size of a small car that pulsed with inner light in complex, shifting patterns.
"The original form," Marcus breathed. "Before the Guild built around it and extended its structure upward."
The core hovered a few feet above the chamber floor, suspended without visible support in the center of the space. Concentric rings were carved into the floor beneath it, each inlaid with smaller crystals that pulsed in rhythm with the core.
"It's beautiful," Alan said, genuinely awed by the sight. The physics principles visible in the Crystal's structure were both familiar and utterly alien—wave patterns he recognized from quantum field theory, but operating at a scale and with an intensity impossible in his world.
Lyra moved carefully around the perimeter, studying the formation. "The energy patterns are different here than in the refinery above. More... fundamental. Less directed."
"The Guild adapted it for power generation," Torbin explained. "Channeling and focusing its natural emanations for practical use."
Alan approached the core, feeling a strong resonance with the data crystal from Ironhammer, which now pulsed rapidly in his pocket. He removed it, and immediately the small crystal aligned itself toward the core, pulling like a magnet seeking its pole.