The Cavity
Long Tian withdrew his fingertips from the chisel marks and hovered in place for a moment.
The chisel mark was located near the bottom of the space, about a meter above his current position. He continued moving upwards along the wall, and the lighting shifted with him, revealing more details on the wall—above the vertical chisel mark, a region of shallow horizontal grooves appeared on the wall surface. The grooves were evenly spaced and densely arranged, like a grid drawn on a stone surface. The grid lines were straight and of uniform depth, forming a precise perpendicular intersection with the angle of the vertical chisel mark. The grid area covered an area about one zhang high and two zhang wide, with the top edge converging into a horizontal line, the end of which had a slightly raised curved outline.
Long Tian stood before the curved outline. It rose slightly above the surrounding stone surface, like a specially preserved protrusion. The Dragon Shadow descended from above and hovered beside him. The light from his forehead converged into a more concentrated beam, illuminating the surface of the curved outline. Under the concentrated light, the outline revealed a clearer shape—a shallow relief circle, about an arm's length in diameter. The relief surface was engraved with dense patterns that spiraled outward from the center, the spirals evenly spaced, circling nine times from the center to the edge. The spirals converged at the outermost edge of the circle into a hook shape, pointing southeast, consistent with the direction of the path he had previously marked on the nautical chart and on land.
Long Tian reached out and touched the surface of the relief. The Origin Return Pearl adjusted its rotation speed again the instant it made contact, with a greater amplitude than before, like a piece of metal automatically deflected in a sensing field when a magnet is brought near it. A subtle ripple began to appear on the relief surface where his palm touched, like the localized increase in water temperature in that small area. As the heat was continuously conducted, the patterns in that area gradually changed from a dark color to a warm gray tone, starting from the center and proceeding segment by segment along the spiral path towards the edge, flowing along each loop until it covered the outer edge of the entire spiral before stopping. After it came to a stop, the relief surface maintained this warm gray tone, without further change or fading.
Long Tian withdrew his hand. The warm gray on the relief lingered even after his hand left, like an old copper surface that had been touched and still retained a faint warmth after the heat of the touch dissipated. Its patterns were now more deeply embedded in the texture of the stone, like a piece of cloth that had been repeatedly soaked and washed, gradually fading its original color to reveal a long-covered base color that was slowly seeping out and spreading along the spiral pattern towards the edges.
The Dragon Shadow, suspended in the water, subtly adjusted its position—its two heads simultaneously turned a few degrees towards the relief, all four eyes focusing on the same hook-shaped end of a spiral pattern, remaining fixed in that position. Long Tian observed the direction of the Dragon Shadow's deflection, then followed the direction of that hook-shaped end, glancing towards the southeast of the space. From this angle, the outline of another wall could be vaguely discerned at the edge of the illuminated area, farther away than the wall he was currently on. Its surface seemed to have similar textures, but the details were blurred by distance and the scattering of water.
He didn't swim towards the further wall for the moment. He paused for a moment before the relief, the rotation speed of the Origin Return Pearl had returned to near normal, and the warm gray of the relief surface was gradually transitioning back to its original color. He memorized the shape of the relief and the number of spirals, then turned and began to swim back. The Dragon Shadow folded back from his side to above his back, its wing membranes folded into a posture suitable for passing through the passage, and the light from his forehead switched from a diffused illumination mode to a directional, focused beam, illuminating the path ahead of him. He followed the path he had come from, passing through the crevice, the corner, and the top of the wall. In the illumination field on his return journey, he saw several fine, dark deposits at the seams on the inner side of the wall. Unlike the grayish-white powder he had seen in the nearshore and mountain halls, these were darker, finer particles, like mineral residue that had settled in the cracks of rocks after being soaked for a long time.
As he surfaced, a crack appeared in the low-hanging clouds of the night sky, revealing starlight that shimmered on the sea, creating a layer of tiny points of light. The man at the stern wasn't at the helm; he was crouching by the gunwale, clutching the rope with the iron weight attached. Seeing Long Tian's head emerge from the water, he remained silent, simply lowering the gangplank by half an inch. Long Tian clung to the gunwale and climbed aboard, water trickling down his clothes and trousers and pooling on the deck. After he boarded, the Dragon Shadow rose from its back to the air above the gunwale, its wings unfolding and shaking off a layer of residual light dust soaked in water. This dust, settling on the deck, continued to glow, like a layer of luminous sand that had been spread out and evenly compacted.
Yu Jin handed over the leather pouch, which Long Tian took and drank a few sips of. He returned the pouch, sat down on the deck, took off his soaking wet boots, wrung out the water from his socks, and then stretched his feet out on the deck to dry. The man at the stern retrieved the rope of the iron weight into the cabin and returned to sit down by the helm.
"There's a large cavity on the inside of that wall." Long Tian straightened his clothes, the luster of the Origin Return Pearl shining through the damp fabric beneath his collar like a wick still burning in cold water. "There's a relief carving on the wall of the cavity, depicting a spiral pattern that circles nine times, ending in a southeast-southeast direction. The crack in the door wasn't created by destruction; it was pre-existing. It was designed to be passable from the beginning, but had never been used."
The man at the stern remained silent in the darkness. He sat at the helm, gazing at the dark sea where the water and night blended seamlessly. After a moment, he spoke, his voice lower than before against the backdrop of the still water. "How much time passed between the moment that crack in the door was left open and until you finally walked through it?"
Long Tian hadn't calculated the time span, but he glanced down at his soaked clothes—the light from the Origin Return Pearl was still shining, steadily and evenly, like water gushing from the bottom of a well, continuously replenishing what was being consumed. He looked up towards the figure at the stern; the figure's silhouette was only a gray shadow in the dim light where the deck and sea met, bobbing up and down with the waves. Long Tian turned his gaze back to the deck in front of him. He spoke softly, but each word struck the grain of the wood. "It's been long enough, long enough that everyone thought the door was just a crack in the wall, not a door. But I went in. Now the crack has been opened, and once opened, it won't return to its original state, like a lock that has been opened and, even if closed again, can never return to its original position after being turned."