He made a hitch by tying a line to the holes in the tips of the skis; there was a long piece left over. He said to Sam, "I'll tie this to my arm. If you want anything, just jerk."

Okay.

"Here we go." Bruce put on his skis, brought the hitch up to his armpits and ducked his head through, forming a harness. He grasped his ski poles and set out to the south, parallel to the cliff.

The toboggan drag steadied him; he settled down to covering miles. Earth was shut off by the cliff; the Sun gave him no estimate of hour. There was nothing but blackness, stars, the blazing Sun, a burning desert underfoot, and the towering cliff-nothing but silence and the urgency to get back to base.

Something jerked his arm. It scared him before he accounted for it. He went back to the toboggan.

"What is it, Sam?"

"I can't stand it. It's too hot." The boy's face was white and sweat-covered.

Bruce gave him a shot of air, then thought about it. There was an emergency shelter in Sam's pack, just a rolled-up awning with a collapsible frame. Fifteen minutes later he was ready to move. One awning support was tied upright to the sole of one of Sam's boots; the other Bruce had bent and wedged under Sam's shoulders. The contraption looked ready to fall apart but it held. "There! Are you okay?"

"I'm fine. Look, Bruce, I think my knee is all right now. Let me try it."

Bruce felt out the knee through the suit. It was twice the size of its mate; he could feel Sam wince. He touched helmets. "You're full of hop, chum. Relax."

Bruce got back into harness.

Hours later, Bruce came across tracks. They swung in from northeast, turned and paralleled the hills.

He stopped and told Sam.

"Say, Sam, how can I tell how old they are?"

"You can't. A track fifty years old looks as fresh as a new one.

"No point in following these?"

"No harm in it, provided they go in our direction."

"Roger." Bruce went back to towing. He called hopefully over the radio every few minutes and then listened. The tracks cheered him even though he knew how slim the chance was that they meant anything.

The tracks swung out from the hills presently or, rather, the hills swung in, forming a bay. He took the shorter route as his predecessor had.

He should have seen what was coming. He knew that he should keep his eyes ahead, but the need to watch his instruments, the fact that he was leaning into harness, and the circ.u.mstance that he was following tracks combined to keep his head down. He had just glanced back at Sam when he felt his skis slipping out from under him.

Automatically he bent his knees and threw his skis into a "snowplow." He might have been able to stop had not the toboggan been scooting along behind. It plowed into him; boy, skis, and toboggan went down, tangled like jackstraws.

He struggled for footing, felt the sand slip under him. He had time to see that he had been caught-in daylight!-by that lunar equivalent of quicksand, a morning glory. Then the sifting dust closed over his helmet.

He felt himself slip, slide, fall, slide again, and come softly to rest.

Bruce tried to get his bearings. Part of his mind was busy with horror, shock, and bitter self blame for having failed Sam; another part seemed able to drive ahead with the business at hand. He did not seem hurt-and he was still breathing. Heisupposed that he was buried in a morning glory; he suspected that any movement would bury him deeper.

Nevertheless he had to locate Sam. He felt his way up to his neck, pushing the soft flakes aside. The toboggan hitch was still on him. He got both hands on it and heaved. It was frustrating work, like swimming in mud. Gradually he dragged the sled to him-or himself to the sled. Presently he felt his way down the load and located Sam's helmet. "Sam! Can you hear me?"

The reply was m.u.f.fled. "Yeah, Bruce!"

"Are you okay?"

"Okay? Don't be silly! We're in a morning glory!"

"Yes, I know. Sam, I'm terribly sorry!"

"Well, don't cry about it. It can't be helped."

"I didn't mean to-"

"Stow it, can't you!" Sam's voice concealed panic with anger. "It doesn't matter. We're goners-don't you realize that?"

"Huh? No, we're not! Sam, I'll get you out-I swear I will."

Sam waited before replying. "Don't kid yourself, Bruce. n.o.body ever gets out of a morning glory."

"Don't talk like that. We aren't dead yet."

"No, but we're going to be. I'm trying to get used to the idea." He paused. "Do me a favor, Bruce-get me loose from these confounded skis. I don't want to die tied down."

"Right away!" In total darkness, his hands in gloves, with only memory to guide him, and with the soft, flaky dust everywhere, unlashing the load was nearly impossible. He shifted position, then suddenly noticed something-his left arm was free of the dust.

He shifted and got his helmet free as well. The darkness persisted; he fumbled at his belt, managed to locate his flashlight.

He was lying partly out and mostly in a sloping ma.s.s of soft stuff. Close overhead was a rocky roof; many feet below the pile spilled over a floor of rock. Sideways the darkness swallowed up the beam.

He still clutched the toboggan; he hauled at it, trying to drag Sam out. Failing, he burrowed back in.

"Hey, Sam! We're in a cave!"

"Huh?"

"Hang on. I'll get you out." Bruce cautiously thrashed around in an attempt to get his entire body outside the dust. It kept caving down on him. Worse, his skis anch.o.r.ed his feet. He kicked one loose, snaked his arm in, and dragged it out. It slid to the base of the pile. He repeated the process, then rolled and scrambled to the floor, still clinging to the hitch.

He set the light on the rock floor, and put the skis aside, then heaved mightily. Sam, toboggan, and load came sliding down, starting a small avalanche. Bruce touched helmets. "Look! We're getting somewhere!"

Sam did not answer. Bruce persisted, "Sam, did you hear me?"

"I heard you. Thanks for pulling me out. Now untie me, will you?"

"Hold the light." Bruce got busy. Shortly he was saying, "There you are. Now I'll stir around and find the way out."

"What makes you think there is a way out?"

"Huh? Don't talk like that. Who ever heard of a cave with no exit?"

Sam answered slowly, "He didn't find one."

"Look." Sam shined the light past Bruce. On the rock a few feet away was a figure in an old-fashioned s.p.a.ce suit.

Bruce took the light and cautiously approached the figure. The man was surely dead; his suit was limp. He lay at ease, hands folded across his middle, as if taking a nap. Bruce pointed the torch at the gla.s.s face plate. The face inside was lean and dark, skin clung to the bones; Bruce turned the light away.

He came back shortly to Sam. "He didn't make out so well," Bruce said soberly. "I found these papers in his pouch. We'll take them with us ~so we can let his folks know."

"You are an incurable optimist, aren't you? Well, all right." Sam took them. There were two letters, an oldstyle flat photograph of a little girl and a dog, and some other papers. One was a driver's license for the Commonwealth of Ma.s.sachusetts, dated June 1995 and signed Abner Green.

Bruce stared. "1995! Gee Whiz!"

"I wouldn't count on notifying his folks."

Bruce changed the subject. "He had one thing we can use. This." It was a coil of manila rope. "I'll hitch all the lines together, one end to your belt and one to mine. That'!! give me five or six hundred feet.

If you want me, just pull."

"Okay. Watch your step."

"I'll be careful. You'll be all right?"

"Sure. I've got him for company."

"Well . . . . here goes."

One direction seemed as good as another. Bruce kept the line taut to keep from walking in a circle.

The rock curved up presently and his flash showed that it curved back on itself, a dead end. He followed the wall to the left, picking his way, as the going was very rough. He found himself in a pa.s.sage. It seemed to climb, but it narrowed. Three hundred feet and more out by the ropes, it narrowed so much that he was stopped.

Bruce switched off his light and waited for his eyes to adjust. He became aware of a curious sensation. It was panic.

He forced himself not to turn on the light until he was certain that no gleam lay ahead. Then thankfully he stumbled back into the main cavern.

Another series of chambers led steadily downward. He turned back at a black and bottomless hole.

The details varied but the answers did not: At the furthest reach of the lines, or at some impa.s.sable ob stacle, he would wait in the dark-but no gleam of light ever showed. He went back to Sam after having covered, he estimated, about 1800.

Sam had crawled up to the heap of fallen dust. Bruce hurried to him. "Sam, are you all right?"

"Sure. I just moved to a feather bed. That rock is terribly cold. What did you find?"

"Well, nothing yet," he admitted. He sat down in the flaky pile and leaned toward Sam. "I'll start again in a moment."

"How's your air supply?" asked Sam.

"Uh, I'll have to crack my reserve bottle soon. How's yours?"

"Mine is throttled to the limit. You're doing all the work; I can save my reserve bottle for you-I think."

Bruce frowned. He wanted to protest, but the gesture wouldn't make sense. They would have to finish up all even; naturally he was using much more air than was Sam.

One thing was sure-time was running out. Finally he said, "Look, Sam-there's no end of those caves and pa.s.sages. I couldn't search them all with all the air in Luna City."

"I was afraid so."

"But we know there's a way out right above us."

"You mean in."

"I mean out. See here-this morning glory thing is built like an hour gla.s.s; there's an open cone on top, and this pile of sand down below. The stuff trickled down through a hole in the roof and piled up until it choked the hole."

"Where does that get you?"

"Well, if we dug the stuff away we could clear the hole."

"It would keep sifting down."

"No, it wouldn't, it would reach a point where there wasn't enough dust close by to sift down any further- there would still be a hole."

Sam considered it. "Maybe. But when you tried to climb up it would collapse back on you. That's the bad part about a morning glory, Bruce; you can't get a foothold."

"The d.i.c.kens I can't! If I can't climb a slope on skis without collapsing it, when I've got my wits about me and am really trying, why, you can have my reserve air bottle."

Sam chuckled. "Don't be hasty. I might hold you to it. Anyhow," he added, "I can't climb it."

"Once I get my feet on the level, I'll pull you out like a cork, even if you're buried. Time's a-wastin'."

Bruce got busy.

Using a ski as a shovel he nibbled at the giant pile. Every so often it would collapse down on him. It did not discourage him; Bruce knew that many yards of the stuff would have to fall and be moved back before the hole would show.

Presently he moved Sam over to the freshly moved waste. From there Sam held the light; the work went faster. Bruce began to sweat. After a while he had to switch air bottles; he sucked on his water tube and ate a march ration before getting back to work.

He began to see the hole opening above him. A great pile collapsed on him; he backed out, looked up, then went to Sam. "Turn out the light!"

There was no doubt; a glimmer of light filtered down. Bruce found himself pounding Sam and shouting. He stopped and said, "Sam, old boy, did lever say what patrol I'm from?"

"No. Why?"

"Badger Patrol. Watch me dig!" He tore into it. Shortly sunlight poured into the hole and reflected dimly around the cavern. Bruce shoveled until he could see a straight rise from the base of the pile clear to the edge of the morning glory high above them. He decided that the opening was wide enough to tackle.

He hitched himself to Sam with the full length of all the gla.s.s ropes and then made a bundle of Sam's pack save air and water bottles, tied a bowline on Sam's uninjured foot, using the manila line and secured the bundle to the end of that line. He planned to drag Sam out first, then the equipment. Finished, he bound on skis.

Bruce touched helmets. "This is it, pal. Keep the line clear of the sand."

Sam grabbed his arm. "Wait a minute."