The Gap in the Door
Long Tian squatted by the gunwale, wiping the water droplets from his face. A person at the stern handed him a dry cloth, which he took and pressed against his hair to absorb the moisture for a while before folding the cloth and placing it on the gunwale.
"I'll try to squeeze through that crack again tonight." He wrung out his soaking wet coat and put it back on, straightening the hem. "This time I'll try to see if I can squeeze through the crack. If I can, I'll figure out the structure inside and come up."
The man at the stern coiled the rope he was holding on the deck, glanced up at him. "Your shadow on the boat already figured out the intermittent patterns of the current, the direction of that wall below. It will follow you when you go down, and correct your course if you stray. If you pass through that gap, your shadow will sense the spatial changes on the other side of the gap before you do."
Long Tian didn't reply. He squatted by the ship's side for a while longer, until his breathing had completely calmed down and his heartbeat returned to normal. Yu Jin came over from the cabin, squatted down next to him, and handed him a leather bag filled with fresh water. Long Tian took it, drank two sips, tightened the stopper, returned it, and then stood up again and walked to the ship's side.
This time, his entry into the water was even more swift than before. He had become accustomed to the impact of the water converging from all sides; his body tensed only briefly as he passed through the thermocline before relaxing. The Dragon Shadow followed his back as they entered the water in sync, the wing membranes retracting into narrow strips suitable for underwater travel. The light from the vertical line on his forehead scattered over a wider area in the water than the first time, like a lamp whose focus had been readjusted, illuminating a greater expanse of water.
He swam along the route he remembered to the crevice at the bend. As he approached, the crevice appeared wider than before due to the change in the angle of the lighting, and the visible space inside seemed deeper. He stopped at the entrance of the crevice and reached out to feel its edge—the cut surface of the stone wall was smooth, not formed by a natural fracture, but polished. The cut surface differed from the weathering of the surrounding walls, as if it had been processed later than the surrounding stone surfaces, maintaining its distinction from the old structure through continuous explanation.
Long Tian squeezed sideways into the crevice. The crevice was just wide enough for him to pass through, but once inside, the space suddenly expanded—no longer a narrow crevice, but a passageway. The passageway followed the direction of the wall's angled extension, with smooth walls on both sides and the floor paved with the same stone slabs as the bottom of the crevice. There was no sediment in the passageway, as if it had been naturally cleaned by a continuous flow of water. The top of the passageway was about an arm's length above his head, so one didn't need to bend over to walk through it. He swam forward along the passageway for a while, his Dragon Shadow rising slightly from its position close to his back. The light from his forehead spread along the passageway walls to both sides, illuminating the patterns carved on the walls segment by segment.
The textures were continuous lines, starting near the entrance and extending inwards along both walls. The lines didn't form a pattern, but rather resembled a series of continuously drawn long arcs, each arc turning and converging at the same point. He followed these arcs to the end of the passage. There was no door or wall at the end—the passage ended in a spacious area, larger than he had ever expected of an underwater structure. It was like an extremely vast and empty interior space completely filled with water, the ceiling far beyond his sight, and the walls barely showing their outlines at the edges of the illuminated area.
He floated in the center of the space, the Dragon Shadow completely detached from his back. It rose into the water for a while, its wings spreading, the wing membranes moving slightly slower underwater than in air, each movement leaving a continuous trail of light. It stopped a short distance above the Long Tian, its four eyes opening wide, looking in four different directions, as if confirming whether the structure of the space it was in corresponded to a certain old path in its memory. The vertical line on its forehead continued to shine in the water, the area covered by the diffused light layer being almost twice as large as in air—not because the intensity of the light increased, but because the water's scattering of light allowed the same brightness of light source to occupy a larger illuminated area with a continuous and stable output, revealing more details on the walls of the space.
Long Tian spotted a mark on the wall at the edge of the light layer's coverage area—a vertical chisel mark extending upwards from near the ground and disappearing at the boundary of the light layer's coverage. He swam closer; the chisel mark was wider and deeper than he had initially seen, with neat edges, as if repeatedly chiseled out by some fixed tool. He placed his fingertip on it, moving it along the chisel mark's direction. The pulsation of the Origin Return Pearl briefly synchronized with the chisel mark when his fingertip touched its surface. The synchronization didn't last long, about a few breaths' interval, but during this interval, he felt the Origin Return Pearl and the new core within his body simultaneously increase their rotation speed—like a pendulum clock whose rhythm had been temporarily adjusted by an external force, returning to its original cycle after the force was removed. The luster of the chisel mark itself left a small, faint bright spot after his fingertip left, which gradually dissolved into the surrounding water as it continued to magnify, like the original writing on a piece of paper gradually becoming blurred and faded by water stains.