When Zena had the grate in place, we set off.
I walked first down the metal corridor. Zena followed uncertainly behind me, tripping once and skidding, though there was nothing there to trip on except her feet. The duct itself, fully six feet wide and six feet high, was made of smooth metal. The darkness was complete except for the occasional grille of light cast into the dust at a grate opening, and the beam cast by my little light. As we passed them, I numbered the grates and the cross-corridors to give me a ready idea of how far from home I was.
As we passed the grates, occasionally noises penetrated from the outside world, but it was clearly another world than the one that we were in. The sounds of our world were the metallic echoes of our whispers, the sound of our sandals padding dully, and the constant sound of the fans.
I had read more than one novel set in the American West two hundred years before Earth was destroyed, where conditions were almost as primitive as on one of the colony planets. I remembered reading of the scouts who even in strange territory had the feel of the country, and I felt much the same way myself. The feel of the air, the sounds, all meant something to me. To Zena they meant nothing and she was scared. She didn’t like the dark at all.
At those points where the corridors joined there were sometimes fans to be ducked. The corridors also sloped at the junctions so that there were no straight corners, and this was disconcerting when the corridor you were meeting ran up-and-down, even when it was the equivalent of a capillary and could be gotten over with one good jump.
Zena balked at the first of these that we encountered and had to be prodded before she would cross it.
“I don’t want to,” she said. “I can’t jump that far.”
“All right,” I said. “But if you don’t come along, you’ll just be left here all alone in the dark.”
That made her mind up for her and she found that she could jump it, and with very little effort, either.
But I’ll have to admit that old-collecting-chute-hand or not, I wasn’t prepared for what we found next. In the darkness, there was no floor in front of us. Above us, no ceiling. My light showed our own corridor resuming on the far side of the gap, fully six feet away. The floor sloped sharply down and the air rushed strongly along. I had never encountered an up-and-down duct of this size before.
“Well, what is it?” Zena asked.
There were handholds at the side on which to cross the gap, and holding onto one of these, I leaned over and dropped a piece of broken chalk in a futile attempt to gauge the depth of the cross-duct. I listened, but I never heard a sound.
“It must connect one level with the next,” I said. “A main line. I bet it goes straight down to the First Level.”
“Well, don’t you know?”
“No, I don’t,” I said. “I’ve never been here before.”
I wasn’t about to jump that distance, so I examined the hand- and footholds carefully. If you slipped and fell, and it was as far down as I suspected, all that would be left of you would be jam. I shone my light up and down, and the beam only managed to nibble at the blackness. The holds went up-and-down, too, as well as across, a ladder that went much farther than I could see.
“Maybe it connects with the Fourth Level down there,” Zena said, “but where does it go to up there?” She pointed straight up the duct.
I didn’t know. The Fifth Level was the very last, the outside, but this duct went beyond the Fifth. Air chutes don’t lead into blind corners and air doesn’t come from nowhere.
“I don’t know,” I said. “But as long as we’re here, why don’t we see where it goes?”
I reached over and put my toe in the inset in the wall. Then I grabbed the first handhold I could reach and swung out. They were good firm holds and while the distance straight down bothered me a little, as long as I couldn’t see how far down it was I wasn’t really scared. I once had the experience of walking along a board three inches wide while it was set on the ground — I went the whole length and probably could have walked on for a mile and never fallen off. Then the board was raised into the air and I was challenged to try again. When it was set on posts ten feet high, I wouldn’t even try it because I knew I couldn’t make it. This was something of a similar situation, and as long as I couldn’t see I knew I wouldn’t worry.
I grabbed the next hold and started up. Before I could get anywhere, Zena leaned over and held me by the foot. “Hey, wait up,” she said, and gave my foot a tug.
“Watch it!” I said sharply. “You’ll make me fall.” I tried to jerk my foot loose, but she wouldn’t let go.
“Come on back down,” Zena pleaded.
Reluctantly I came down. I said, “What is it?”
“You can’t go and just leave me.”
“I’m not leaving you,” I said. “Just follow me and you can’t be left behind.”
“But I’m scared,” she said.
That was really the time for her to finally admit it. We had both known that from the beginning, but she had refused to admit it until things were getting interesting.
“It’s not going to hurt you,” I said. “All we have to do is climb until we find out what’s up there.” I could see she was wavering, caught between the fear of climbing the ladder and the fear of being left behind. “Come on,” I said. “You first.” I wanted her to go first. That way she couldn’t grab me again.
After a moment, I edged her down the beginning of the slope to the first handhold. I got her onto the ladder and actually moving again. I followed her. I had the light clipped at my waist, pointing upward and giving both of us some idea of what and where to grab as we continued to climb.
I could hear Zena whimpering as she climbed, making scared noises in her throat. To get her mind off her troubles, I said, “Can you see anything up there?”
She was clinging tightly to the ladder as we went up, and now she stopped, flipped her head up for just the shortest instant and then brought it down again.
“No,” she said. “Nothing.”
I should have known better, I told myself as we continued to climb. You don’t bring somebody who has a habit of choking up into a situation like this.
Suddenly, without any warning, Zena stopped moving. Before I could help myself, my head rammed so hard into her foot that a shock of pain ran through my neck. If I’d had my head up, I would have seen that she’d stopped, but you can’t climb indefinitely with your head thrown back without getting a crick in your neck. I stopped immediately and went down one step.
“What’s the matter?” I asked.
“I just can’t go any farther. I can’t.”
I lifted my head and peered upward. I couldn’t see anything beyond Zena that would hold her up. She was just clinging to the ladder, her face pressed close to the metal. I could hear her breath rasp in her throat.
“Did you run into something?”
“No. I just can’t go any farther,” she said tearfully. “I’m scared.”
I reached up and put my hand on her leg. It was rock-hard and trembling. I said, “Move ahead, Zena,” in a firm but gentle tone — I didn’t want to frighten her — and pushed at the calf of her leg, but she didn’t move.
I could see that it had been a mistake to be in the lower position on the ladder. If Zena let go and fell, I would be swept along no matter how hard I tried to hold on. That would save me trying to explain what had happened — and it might be difficult to explain if I came back by myself without Zena: “Oh, she fell down one of the air chutes” — but that wasn’t anything to be happy about. I was genuinely frightened. My heart was beginning to speed up and I could feel a trickle of sweat running down my back.