The space was enormous.
That was the first thing he understood, and he understood it before his eyes had finished adjusting. Scale had a feeling before it had a shape. He stood at the tunnel mouth and felt the cavern push back at him. Just weight. Just size. The tunnel had been close and cold and nothing, and now there was this.
His eyes caught up slowly.
The cavern ceiling was high. How high he could not say with any confidence. The light in here was dim and sourceless, the kind that seemed to come from the rock itself rather than from anywhere specific, and it faded before it reached the top. He looked up and found grey fading into grey and stopped looking. The ceiling was either very far away or the light simply gave up at a certain point. Either way, knowing the number would not help him.
The walls to his left and right were closer. Close enough to see that they were rough where the tunnel had been smooth, fractured rock in long diagonal lines, as if something enormous had pulled this space open rather than carved it. He was standing on a ledge. Maybe three metres of flat stone between the tunnel mouth and the edge.
He did not look at the edge yet.
He looked at what was in front of him instead.
The bridge began at the ledge and went forward until it did not.
Nine metres wide, he estimated. Wide enough that a person standing in the middle could not touch either railing without moving. The surface was old wood, dark with age, the planks running crosswise. The railings on each side were wood too, waist-height posts connected by two horizontal rails, nothing more. No roof. No walls. Just the structure itself, going out across the cavern and disappearing into the grey distance.
He looked for the far end.
There was none. The bridge went on until the light failed and the grey swallowed it and there was nothing to see anymore. He stood and looked for a long time, thinking his eyes might find something. They did not. The bridge simply continued past the point where seeing was possible.
To the right of where the bridge began, close enough to reach without stepping onto the structure, a sign was fixed to a post driven into the ledge. Old wood, the letters cut deep and filled with something dark so they would hold.
He walked to it and read it.
CROSS IT TO REACH SALVATION.
He read it twice. Then he looked back out at the bridge, at the place where it disappeared, and back at the sign.
'Salvation.'
He did not know what that meant. He turned away from the sign and looked at the edge of the ledge.
The cavern below was dark.
Not the dark of the tunnel, which had been merely the absence of light. This was a different quality of dark. The tunnel dark had felt temporary, the kind that ends. This dark had depth to it, more depth than dark alone could account for. He stood at the edge of the ledge and looked down and his eyes told him there was a bottom somewhere but his gut told him his eyes were wrong.
He needed to know.
He stepped back from the edge and looked along the ledge for a loose stone. Found one near the tunnel mouth where the floor had crumbled slightly, a piece of rock roughly the size of his fist. He carried it back to the edge and held it out over the drop, arm extended, and let it go.
He watched it fall. It dropped fast, and within two seconds it had passed out of the dim light and into the dark below. He kept watching the dark. Kept listening.
Nothing.
No impact. No distant clatter. No echo of stone on stone. The rock went into the dark below and the dark absorbed it completely, and the silence that followed was the same silence as before, unchanged, as if the rock had never existed.
He straightened up.
He had known, in a loose way, before he dropped the stone. The look of the dark below had told him something. But knowing it loosely and knowing it precisely were different things, and the silence after the drop was precise. There was no bottom. Or if there was, it was so far down that the sound of impact could not make the journey back. For practical purposes those were the same thing.
He looked at the bridge. At the railing posts, at the planks, at the dark on either side of the structure where the void waited.
Nine metres wide. The railing was waist height. If a plank gave way, or if he lost his footing on the edge, there was nothing between him and a drop that had no recorded end.
He stood with that for a moment.
He went back to the sign and read it again, not because he expected it to say something different but because he needed something to do while he thought.
CROSS IT TO REACH SALVATION.
The alternative was the tunnel. He could go back. Sit in the cave and wait, the way he had considered waiting before the first door, the same option it had been then. The tunnel was behind him. The cave was at the end of it. Neither offered food or water or any reason to think that staying would produce a different result than what he had now, which was nothing.
The bridge went somewhere. It had to. Things were built for purposes. Someone had constructed this, had sunk these posts and laid these planks across a bottomless drop, and they had not done it for no reason. Wherever the bridge ended there was something, and whatever that something was it was more than the cave had offered.
That was the logic of it. Clean and simple and not quite enough to move him yet.
He looked at the drop again.
Fear was still there. The same feeling that had arrived at the end of the tunnel, the first named thing he had felt. He was not going to pretend it wasn't. It was a reasonable response to standing at the edge of a bottomless pit in an unknown cavern with no supplies and no memory and a sign telling him the path forward was across nine metres of old wood above nothing.
He was afraid and the bridge was still there and the tunnel was still behind him.
He picked up another stone from the tunnel mouth, smaller this time, and walked to the start of the bridge. He crouched and pressed his palm flat against the first plank. The wood was hard and cold and dry. He pressed harder, testing, rocking his weight forward onto it. It did not flex. He moved his hand to the next plank. Same. He worked his way across the width of the bridge on his hands and knees, pressing each plank at the near end, checking the joints where they met the crossbeam beneath.
Solid. Old but solid.
He stood up. Looked along the bridge to where it disappeared. Looked down at the dark on either side of the planks beneath his feet. The void was right there. A step sideways and it would have him.
'Don't step sideways.'
He held the small stone out and dropped it without ceremony, the same as before. Same result. The dark took it and gave nothing back.
He put both hands on the railing, and stood at the start of the bridge for a while longer. The cold air moved past him from behind, from the tunnel, as if the cave itself was breathing out. He let it push at him. Let the silence sit. Let the bridge be what it was without arguing with it.
Then he took his hands off the railing, put them at his sides, and looked straight ahead down the length of the structure to the place where it vanished.
Salvation, the sign said.
He did not know what that meant. He knew what it cost to find out.
He took the first step.
Then he stepped back off.
He stood on the ledge again with both feet on stone and looked at the plank he had just been standing on. Nothing had happened. The wood had held, the bridge had not moved, there had been no sound and no sensation beyond the cold through his soles. He had simply stepped back without deciding to.
He stood there for a moment. Then he stepped on again, this time keeping his weight forward, and kept moving.