The night Elara returned from the ruins, she couldn't sleep. Kael's hideout—a secret living space carved from the hollow roots of a windbone tree—had thin phosphorescence seeping through its stone walls, peculiar to Aeselia's nights. Each time the island trembled, fine sand fell faintly from the ceiling. Kael lay with his back to the wall, impossible to tell if he was awake or asleep. Elara hugged her knees on top of a blanket, the Prism resting in her palm. An octahedron crystal. Small enough to fit in her hand, yet it carried an odd weight. The liquid light within continued to pulse quietly through the night, its fluctuation growing faintly but distinctly stronger at one particular point. (There's something in that direction.) In the ruins of the Ash Archipelago, the Prism's engravings had matched the wall paintings' emblems. Palimpsest—the ancient hypercivilization that vanished without a trace roughly 1,200 years ago—an artifact of that lost world. The Great Erasure—the historical revision incident where all records, memories, and physical traces of that civilization were simultaneously deleted from all dimensions—she was certain of its connection. But the direction the pulsing light pointed was not north. It was down. Every time she tilted the Prism, the light oriented toward the ground. Beneath this island. Beneath the cloud sea. Even deeper than the Void, the unexplored region they called it. "You're not sleeping again," Kael said. Kael didn't move, still facing the wall. "The Prism is pointing downward," Elara said. "Down," Kael repeated. "Below the cloud sea. I think there must be an entrance to another dimension. Just like there was a veil between Aeselia and the mortal world, if there's one here too—" Elara said. "That's not something to think about tonight," Kael said. The response came without hesitation. His voice was flat, emotionless. Elara closed her mouth. She knew Kael was right. A veil—the thin boundary separating dimensions—required preparation and planning to cross. The incident at the ruins yesterday, where they'd stumbled upon resonance entities without a plan, was proof enough. Still, the light pointed downward. —— The next morning. Elara spread a map before Kael, showing him the direction and angle where the Prism had reacted, measurements she'd taken again last night. The points concentrated in one location. A place where the veil was thin across Aeselia's archipelago—a record indicating a point where the boundary between dimensions had weakened. "There's apparently a dimension called Luminal Deep," Elara said. "Where did you hear that," Kael asked. "From Oran Kaise at the Wind-Reading Tower, when he was talking about the veils between dimensions. He said it's a subterranean dimension, entirely cavern systems. He mentioned that luminescent creatures and minerals serve as light sources," Elara said. "Is that from someone who's been there, or from texts," Kael asked. It was a sharp question. Elara thought for a moment before answering. "From texts. So I'm not sure how accurate it is. But—" Elara said. She placed the Prism on the map. The light pulsed, rhythmically, in the downward direction. Kael watched silently for a while. Then he slowly traced the map with his fingertip, confirming one by one the points indicating places where the veil was thin. "...I've never crossed a veil before. Never gone from this dimension to another," Kael said. "The Prism might let us cross. The same way we came from the mortal world to Aeselia," Elara said. "That's not guaranteed," Kael said. "I know," Elara said. Silence. Amber eyes looked at Elara. They resembled the eyes he'd had yesterday in the ruins, when he'd said "do as you like" while squeezing through collapsing walls. Eyes mixed with caution and an intent to hide it. "I understand the Prism is pointing downward," Kael said. "How do we cross the veil," Elara asked. "...We should just try," Kael said. He said it with a bitter expression. Elara took it as consent. —— The sensation of crossing the veil was completely different from coming from the mortal world to Aeselia. That time had been quiet, like being drawn into light. This time was turbulent. Gravity vanished for an instant, then pressure came from all directions at once. Elara gripped the Prism tightly in her hand, concentrating only on maintaining consciousness. "—!" Kael gasped. Right beside her, she heard Kael's breath catch—a raw reaction, nothing like his usual composed voice. They landed. The ground was hard. Stone. Elara knelt and slowly raised her head. ——She saw it. Everything was glowing. The ceiling stretched high, its extent unknowable. Walls and floor were covered entirely in moss that glowed with a pale blue light. Countless thin stone formations hung from the ceiling, each one faintly luminescent. The same landscape continued deeper and deeper. Left, right, up—no matter where she looked, everything glowed. Beautiful, she thought. But before that thought could settle, another sensation came. (Every direction looks the same.) "...Every direction looks the same," Kael said. Rarely, he'd said exactly what Elara was thinking. His voice held no humor. "Your sense of direction disappears. The light comes from all directions, so there are no shadows. Without shadows, you can't judge distance," Elara said. "Academic analysis can wait. Which way do we go," Kael said. "I'll measure with the Prism. We'll go toward where it reacts," Elara said. She held the Prism horizontally and slowly rotated it, observing the light's fluctuation. She checked all four directions. When she moved forward, the light seemed to strengthen slightly. "This way," Elara said. Her reasoning was only "it seemed to." But there was no other clue. Kael said nothing. He simply followed. They walked through the cavern. At each fork, Elara measured with the Prism and chose the direction where it reacted. She had no sense of how long they'd been walking. Her sense of distance had completely collapsed, making it impossible to judge whether they were close or far. Their footsteps echoed loudly against the stone floor. Once, Kael stumbled on a ceiling stalactite and let out a small curse. "The light is getting stronger than before," Elara said. "Maybe your eyes are just adjusting," Kael said. "No. The Prism is warm. Try touching it," Elara said. She held it out. Kael hesitated for a moment, then gently touched it with his index finger. He pulled his hand back immediately. "...You're right," Kael said. His voice was matter-of-fact, not surprised. Immediately after, a faint sound came from beyond the rocks ahead. Elara stopped. Kael stopped too. Both of them listened carefully. The sound was—pages turning. —— Peering around the rocks, a cavern opened up. It was vast. The ceiling was high, the pale blue moss light stable and strangely calming in its brightness. One wall was lined with shelves in neat rows. The shelves were packed with manuscripts—volumes of varying sizes with mismatched spines, yet arranged at precise intervals. In the center of the cavern sat a large stone table with a lens-shaped mineral placed upon it, and beneath its light, an open manuscript. Before the table sat a girl. She had long silver-white hair loosely braided, with one section draped over her shoulder. A small ornament hung from her left ear, catching the cavern's light with a faint shimmer—a phosphorescent mineral ornament, Elara realized. Her posture was perfectly straight, absorbed in reading the manuscript. She appeared slightly younger than Elara. Around fifteen, perhaps. Her height was small, but her bearing carried a unique quietness. Not nervousness or tension, but rather—the composure that came from the certainty that this place was hers. "The Sacred Archive—the library that houses Luminal Deep's phosphorescent manuscripts—hasn't had visitors often," the girl said without looking up, still focused on the manuscript. "But two at once is a first. I can see the entrance, so I noticed from the beginning," she continued. Elara exchanged a glance with Kael. Kael opened his mouth slightly— "We got caught pretty early. Awkward," Kael said. It was an apology mixed with levity. The girl's gaze shifted toward him. Her pale violet eyes looked at Kael's face for a second, then immediately moved to Elara. There was judgment in that look. Not assessment, but—information gathering. "I'd like you to leave. This archive is a private research facility. Unauthorized entry is not permitted," the girl said. "I'm, I'm sorry. But—" Elara said. "No 'buts.' Regardless of your reasons, trespassing remains trespassing," the girl said. "That's true, but—" Kael said. "I'd prefer if you remained silent," the girl said. Kael closed his mouth. It was a rare sight, Elara thought. The girl stood and took a few steps toward them. Up close, Elara could see how the mineral ornament refracted the archive's light in complex ways. Her expression was stern, but not angry. Confused and cautious. "You're carrying a Prism," the girl said. "Huh," Elara said. "In your right hand. It's glowing," the girl said. Elara opened her palm. The Prism had grown noticeably warmer since entering the archive. The liquid light inside had activated, pulsing more intensely. The girl's eyes changed. The sternness remained, but something else ignited behind it. (I know that look. She knows something.) Elara spoke on instinct. "This is reacting to something here. The Prism is. Something in this archive," Elara said. "Explanations can wait until you've left," the girl said. "The manuscript spines on the shelf. The leftmost shelf, third row from the top. That engraving—" Elara said. The girl stopped. "An octagon with seven lines inside. That's a Palimpsest emblem. I saw the exact same one in the Aeselia ruins. The Prism has the same engraving too. You know about it, don't you. About the Great Erasure," Elara said. Silence fell. The girl's gaze moved from Elara's face to the Prism, to the manuscript on the shelf, and back to her face. The whole exchange took about three seconds. "...I'm aware of the term 'Great Erasure,'" the girl said. It was more a question than confirmation. "I know about it. Roughly 1,200 years ago, all records and memories of Palimpsest civilization were simultaneously deleted from all dimensions. I don't think it was a natural collapse," Elara said. Three seconds became longer this time. Elara continued. The words wouldn't stop. "Deletion from all dimensions simultaneously isn't a natural phenomenon. Records accumulated over hundreds or thousands of years don't vanish in an instant. It's not physically possible. I think someone deliberately—from within—erased it. And the Prism is an artifact from that civilization, kept in my grandmother's house. When the great veil rupture happened in Eldria eighty years ago—" Elara said. "Wait a moment," the girl said quietly, interrupting. The girl didn't move for a while. Her gaze turned inward, the face of someone thinking. Then, slowly, she turned back toward the shelf. "...You may sit. Please use the translation desk," the girl said. It was a voice completely different from the one that had been trying to drive them away. —— The translation desk—where the girl used phosphorescent minerals as a light source and had built her own magnification device to decipher manuscripts—was laid out neatly on the stone table. Multiple lenses were fixed at different angles, and when a manuscript was placed beneath them, fine details became magnified. Elara could tell the girl used this tool daily. There were many scratches, but it was handled with care. Elara and the girl sat side by side at the translation desk. Kael stood a short distance away. The girl took out one manuscript. A phosphorescent manuscript—the record medium supposedly used by Palimpsest, with approximately 340 volumes housed in this archi