Beyond the Stone Door
Long Tian hovered at the edge of the opening for a moment, allowing the surging airflow to completely stabilize. The frequency of the bubbles was relatively high in the first few breaths, then gradually decreased, becoming a slow, intermittent release, as if the internal and external air pressures were gradually approaching equilibrium. After confirming that there was no irritating odor in the airflow, he withdrew his hand and squeezed into the space below from the edge of the opening.
He stepped onto the dry stone surface. The moment his boots landed, he felt the difference—all the places he had stepped on before were surfaces soaked by seawater, but this place was dry. His feet were touching an old stone surface that had been kept dry for a long time, with a very thin layer of weathering, as if years of air contact had worn the rough particles on the surface into a smooth old surface.
He looked down and observed his surroundings. Below the opening was a short, sloping staircase with about seven or eight steps, leading to a short, horizontal corridor. The corridor extended to both sides, but the left side was blocked by a stone wall about ten feet away, while the right side continued for a distance before turning into a more open space. The stone surface at the top of the corridor was flat, with inscriptions at intervals, arranged in straight lines along the longitudinal direction of the corridor.
After Long Tian confirmed it was safe, Yu Jin followed. His boots made a clear sound as he landed, bouncing several times in the corridor before dissipating. Once steady, he slightly brightened the light from the dark gray bead, bringing a section of the latter half of the corridor into view. This made the corridor's structure appear more clearly defined under the superposition of the two different colors of light. After both of them entered the air chamber, Dragon Shadow retracted its wing membrane and descended from the opening, like a folded flag placed back in its box. Entering the narrower space, it automatically adjusted the wing membrane's posture to adapt to the corridor's height. The light from its forehead continued to provide basic illumination while maintaining an angle that matched the surrounding environment, allowing the most prominent structural features of the space to extend from the entrant's line of sight all the way to the end of the path.
Long Tian walked about ten feet to the right along the corridor. At the end of the corridor was a stone door—the door panel was made of a single piece of dark gray stone, with a smooth surface and extremely narrow seams between the edges and the door frame, leaving almost no extra space. There were no handles or keyholes on the door, only a symbol he had seen before engraved in the center: three overlapping wavy lines. It was exactly the same as the pattern on the sea fish skin paper, and also exactly the same as the engraving on the stone slab in the mountain hall.
He stopped in front of the door. After he stopped, the Dragon Shadow descended from the corridor and hovered beside him. At that moment, the light layer on his forehead slightly adjusted its angle, switching from diffused lighting to a more concentrated beam of light that shone on the symbol on the door panel. Under the concentrated light, the symbol presented a texture different from the surrounding stone surface, like an old carving that had been covered by a protective layer for a long time, gradually revealing its original depth under continuous light.
Long Tian reached out and pushed the door. The door didn't move. He applied more force, but the door still didn't react. Yu Jin came up from behind, placed his palm on the door, and pushed it alongside Long Tian —the door remained in place, like a seamless structure with no contact surface with the door frame, reflecting the reaction of all the force applied to it being evenly distributed and absorbed under continuous force.
Long Tian withdrew his hand and examined the wave symbols on the door panel surface again. He recalled the two rows of symmetrically arranged symbols he had seen at the edge of the underwater concave surface—the arrangement of those symbols might correspond to the three-wave pattern symbols on the door panel; one set corresponded to the opening conditions, and the other to the identification steps. If there was a hierarchical relationship between the arrangement of the two rows of symbols and the symbols on the door panel, then the order of the symbols at the edge of the underwater concave surface might be able to deduce the sequence of operations that needed to be performed on the door panel surface when opening the door. He recalled the arrangement and relative positions of the two rows of symbols—the left row extended from the entrance towards the crack, and the right row extended from the crack towards the entrance, like a ruler that had been bisected and spread out in opposite directions, forming two independent sequences through continuous comparison.
He crouched down in front of the door and ran his fingers along the seams of the door panel. Near the bottom of the door, close to the frame, he felt a slight unevenness—like a row of shallow grooves arranged in parallel, their spacing and depth matching the symbols on the edge of an underwater concave surface. He placed his left palm flat against the bottom edge of the door panel, allowing the energy from the Origin Return Pearl to seep into the shallow grooves along his palm. The energy flowed inwards along the grooves for a while, but was blocked by an invisible resistance at a certain point, like flowing to the end of a clogged drain.
Yu Jin also crouched down, placing his palm on the shallow groove on the opposite edge of the door panel. The light from the dark gray bead flowed through his palm into the groove, mingling with the energy introduced by Long Tian, flowing simultaneously from both sides towards the center within the groove. When the two energies converged in the middle of the groove, they created a brief resonance, like two copper bells struck simultaneously, their lingering echoes overlapping. As the resonance reached the surface of the door panel, the engraving of the wave symbol shone with a uniform gray light in the afterglow of the resonance. The light gradually converged from the edge of the engraving towards the center of the door panel, like a stream of water being continuously poured into a container, expelling the air from within layer by layer.
As the light layer converged to its center, the door panel vibrated in unison with the opening of the underwater concave surface. After the vibration lasted for about two breaths, the door panel began to slowly rotate inward along a central axis he had not previously noticed. The rotation was smooth and slow, like a door, counterweighted by a heavy balancing device, being restarted after a long period of disuse, opening a crack about a hand's width at its designed speed. A stream of air different from that in the corridor rushed out of the crack—warmer, drier, with a very faint dusty smell, like the lingering smell of old air accumulated in a long-sealed space being stirred up by external airflow for the first time, stirring up the sediment that had accumulated in the corners. Although the dust had settled to the bottom layer over time, the smell surged up as the airflow rolled it up again, slowly spreading between the remaining space and the corridor space.
Long Tian squeezed through the crack in the door and entered the space behind it. Yu Jin followed behind him, and the two stood behind the door. After they entered, the Dragon Shadow retracted its wing membrane through the crack and re-unfurled in the space above them. This space was more spacious than the outer corridor—about two zhang square and one and a half zhang high. The walls of the room were polished, their surfaces covered with dense patterns, as if long-term exposure to light and airflow had created a composite layer that blended with the original carvings. In the center of the room, embedded in the floor, was a disc made of the same material as the dark stone slab at the bottom of the underwater concave surface. It was about two chi in diameter, and its surface had a very shallow relief, engraved with two rows of symbols identical to those on the edge of the underwater concave surface, only the spacing between them was slightly larger, and the outlines of the symbols were clearer, as if they had been meticulously refined and compared before being carved. The complete version. On the wall directly opposite the entrance was an engraving—a more complete and detailed map than any Long Tian had seen in the East Sea Cave, the Mountain Hall, or Tang San's sketch. It was a route map composed of multiple lines, the density and direction of which were finer than the versions seen on paper before. Each line ended with a symbol marking its conclusion, and a circular mark marked the center of the map. The pattern of the mark was exactly the same as the surface texture of the dark gray bead Long Tian had seen in the stone house. Long Tian stood in front of the map, his gaze extending from the beginning of each line along the direction of each branch until it finally stopped at the circular mark in the center. He lingered at the edge of that mark for a longer time than he had looked at any other part of the map.