The Arc's End
The ship traveled for nearly two hours along the extended direction of the arc. The sea surface did not change significantly during this voyage; there were no color bands, no unusual water layers, and even the direction of the ocean current remained uniform from southwest to northeast, as if it were a stable waterway flowing through this vast area.
Long Tian squatted at the bow of the boat, periodically checking the water temperature with his hand to ensure the boat remained on course. The water temperature remained stable throughout the voyage, only occasionally fluctuating slightly due to a thin, warm film formed on the surface by sunlight, but quickly returning to normal. The light from Dragon Shadow shone above his shoulders, its direction always aligned with the extended line the bow was pointing, without any deviation.
As the sun began to set, a very faint color change appeared on the sea ahead. Unlike the previous light-colored bands and water-colored bands, this change was more subtle, as if the transparency of the seawater had slightly increased in a certain area, allowing light to penetrate deeper into the water layer than the surrounding areas. Long Tian stood up at the bow of the ship, squatted by the gunwale, and looked at the area of change for a while. The color of the sea in that area was half a degree lighter than the surrounding area, as if the water layer was thinner.
The person at the stern adjusted the rudder, directing the bow directly into the center of the transparency change zone. The instant they entered the boundary of the change zone, a different tactile sensation came from the bottom of the boat compared to when passing through other color bands—the boat's speed did not increase or decrease significantly, but the way the hull contacted the water surface seemed to change slightly, as if they were passing through a different layer of water than the surrounding area.
Long Tian looked ahead along the center line of the changing zone. In the direction of the setting sun, a silhouette was slowly becoming clear—unlike anything he had seen before. It didn't have the height and curvature of an island, nor the broken edges of a reef. It was a low, horizontally extending straight line, spreading out along the sea surface, like a uniform bulge illuminated by horizontal sunlight.
As the ship approached its silhouette, it continued to extend its length. It was not a short line, but a long, straight structure that stretched for at least several tens of feet across the sea, its ends disappearing into the distant mist and halo. In the twilight, its surface took on a dark color similar to the seawater, but its material differed from the seawater's reflection, as if covered by a uniform, non-light-absorbing surface.
Long Tian stood up at the bow and walked along the ship's side to the very front, leaning against the railing and looking forward as far as he could. As the ship drew closer, the horizontal structure gradually revealed more details—its surface was smooth and stable, as if it had undergone a long period of smoothing. The boundary where its edge met the seawater was clear, maintaining its angle with continuous contact. Each section presented a consistent arrangement, like the edge of a stone slab that had been cast and then paved, maintaining its color and texture difference from the surrounding seawater within a continuous range.
The boat stopped a few feet from the edge of the transverse structure. The man at the stern lowered the anchor, securing the boat in the relatively shallow water. Long Tian crouched by the gunwale, watching the structure's outline in the twilight, maintaining a stable position in the constantly shifting field of vision, preserving its own dimension before the light changed. He spread the Dragon Shadow's light layer along the surface of the structure, the light layer extending forward a distance after touching the edge, illuminating its texture—the same as the underwater paving surface, but also the same as the air chamber of the keel base, and the same as the floor of the secret chamber within the base's air chamber.
Long Tian squatted at the bow for a long time, watching until dusk completely disappeared and starlight filled the sea. The horizontal structure faded into darkness in the afterglow of the low-angle lighting. He squatted at the bow for a while longer before standing up, walking back to the hatch, and sitting down, pulling his coat collar tighter. Yu Jin sat inside the hatch, the light from the dark gray bead automatically brightening a level in the night, illuminating a small area of the cabin with a warm and even glow. The person at the stern squatted down, tidying up the probe, wiping the wear marks on the old lead weight at the end of the probe with his fingers to confirm that it was still usable.
Long Tian spoke up, "That structure stretches very far, with no end in sight. It's not an island, nor is it a naturally formed rock formation. It's a horizontally extending man-made structure, with a smooth surface and a texture that matches the ground and its base in the sunset. One edge protrudes above the sea, but most of it remains underwater. It looks like the top of a long wall built at sea level."
He sat down on the deck, leaning against the cabin wall, gazing for a while at the vague outline of the structure under the starlight. The Dragon Shadow's light layer maintained its illumination above the bow, while the vertical line on his forehead remained at a low brightness level after nightfall, enough to illuminate a small area in front of the bow without excessively depleting the reserves. Yu Jin handed him a water bag from the cabin, which Long Tian took, unscrewed, drank half a sip, then tightened the cap and returned it. He leaned against the cabin wall and closed his eyes, as if organizing a path he had already rehearsed many times in his mind, matching each segment to its appropriate location, preparing to see the full picture of the horizontal structure after dawn the next day, and then determine the next point of entry.