"How much water left?" asked Astro thickly.

"Enough for one more drink apiece," Tom replied.

"And then what happens?" mumbled Roger through his cracked lips.

"You know what will happen, Roger—you know and I know and Tom knows," muttered Astro grimly.

For eight days they had been struggling across the blistering shifting sands, walking by night, sweltering under the thin space cloth during the day. Their tongues were swollen. Scraggly beards covered their chins and jaws. Roger's lips were cracked. The back of Tom's neck had suffered ten minutes of direct sun and turned into a large swollen blister. Only Astro appeared to be bearing up under the ordeal. There was no sign of their being close to the canal.

"Wanta try marching during the day?" asked Astro. They had broken camp on the evening of the eighth day and were preparing to move on into the never-changing desert.

"If we don't hit the canal sometime during the night, there might be a chance it's close enough to reach in a couple of hours," replied Tom. "Either that, or we've miscalculated altogether."

"How about you, Roger?" asked Astro.

"Whatever you guys decide, I'll be right in back of you." Roger had grown steadily weaker during the last three days and found it difficult to sleep during the hours of rest.

"Then we'll keep marching tomorrow," said Astro.

"Let's move out," said Tom. Roger and Astro shouldered the remaining slender food packs, with Tom carrying the water and space cloth, and they started out into the rapidly darkening desert.

Once again, as on the previous eight nights, the little moon, Deimos, swung across the sky, casting dim shadows ahead of the three marching boys. Tom found it necessary to look at the compass more often. He couldn't trust his sense of direction as much as he had earlier. Once, he had gone for two hours in a direction that was fifty degrees off course. The rest stops also were more frequent now, with each boy throwing his pack to the ground and lying flat on his back, to enjoy the cool breeze that never failed to soothe their scorched faces.

When the sun rose out of the desert on the morning of the ninth day, they stopped, ate a light breakfast of preserved figs, divided the juice evenly among them, and, ripping the space cloth into three sections, wrapped it around themselves like Arabs and continued to walk.

By noon, with the sun directly overhead, they were staggering. At two-thirty the sun and the heat were so overpowering that they stopped involuntarily and tried to sit on the hot sand only to find that they couldn't and so they stumbled on.

Neither Roger nor Astro asked for water. Finally Tom stopped and faced his two unit-mates wobbling on unsteady legs.

"I've gone as far as I can without water. I—I don't think I can go another step. So come on, we'll finish what we've got."

Astro and Roger nodded in quiet agreement. They watched with dull eyes as Tom carefully opened the plastic container of water. He gave each a cup and slowly, cautiously, measured out the remaining water into three equal parts. He held the container up for a full minute allowing the last drop to run out before tossing the empty bottle to one side.

"Here goes," said Tom. He wet his lips, placed a wet finger on his temples and sipped the liquid slowly, allowing it to trickle down his parched throat.

Roger and Astro did the same. After he had wet his lips, Astro took the full amount in his mouth and washed it around, before swallowing it. Roger brought the cup up slowly to his mouth with trembling hands, tipped it shakily, and then before Astro or Tom could catch him, fell to the ground. The precious water spilled into the sand.

Tom and Astro watched dumfounded as the dry sand sucked away the water until nothing remained but a damp spot six inches wide.

"I guess—" began Tom, "I guess that about does it!"

"We'll have to carry him," said Astro simply.

Tom looked up into the eyes of his unit-mate. There he saw a determination that would not be defeated. He nodded his head and stooped over to grapple with Roger's legs. He got one leg under each arm and then tried to straighten up. He fell to the sand and rolled to one side. Astro watched him get up slowly, wearily, his space-cloth covering remaining on the ground, and then, with gritted teeth, try once more to pick Roger's legs up.

Astro put out his hand and touched Tom on the shoulder. His voice was low, hardly above a whisper. "You lead the way, Tom. I'll carry him."

Tom looked up at the big Venusian. Their eyes locked for a moment and then he nodded his head and turned away. He pulled out the pocket compass and through blurred vision read the course beneath its wavering needle. He waved an arm in a direction to the right of them and staggered off.

Astro stooped down, picked Roger up in his arms and slowly got him across his shoulders. Then steadying himself, he walked after Tom.

Suddenly a blast of wind, hot as fire, swept across the sandy plains, whipping the sand up and around the two walking figures, biting into exposed hands and faces. Tom tried to adjust his goggles when the sand began to penetrate around the edges but his fingers shook and he dropped them. In a flash, the sand drove into his eyes, blinding him.

"I can't see, Astro," said Tom in a hoarse whisper when Astro staggered up. "You'll have to guide."

Astro took the compass out of Tom's hand and then placed his unit-mate's hand on his back. Tom gripped the loose folds of the space cloth and uniform beneath and struggled blindly after the big cadet.

The hot sun bore down. The wind kept blowing and Astro, with Roger slung across his back like a sack of potatoes and Tom clinging blindly to his uniform, walked steadily on.

He felt each step would be his last, but with each step he told himself through gritted teeth that he could do ten more—and then ten more—ten more.

He walked, he staggered, and once he fell to the ground, Tom slumping behind him and Roger being tossed limply to the scorching sand. Slowly Astro recovered, helped Tom to his feet, then with the last of his great strength, picked up Roger again. This time, he was unable to get him to his shoulder so he carried him like a baby in his arms.

At last the sun began to drop in the red sky. Astro felt Roger's limp body slipping from his grip. By now, Tom had lost all but the very last ounce of his strength and was simply being pulled along.

"Tom—" gasped Astro with great effort, "I'm going to count to a thousand and then—I'm going to stop."

Tom didn't answer.

Astro began to count. "One—two—three—four—five—six—" He tried to make each number become a step forward. He closed his eyes. It wasn't important which way he went. It was only important that he walk those thousand steps, "five hundred eleven—five hundred twelve—five hundred thirteen—"

Involuntarily he opened his eyes when he felt himself climbing up a small rise in the sand. He opened his eyes and ten feet away was the flat blue surface of the canal they had been searching for.

"You can let go now, Tom," said Astro in a voice hardly above a whisper. "We made it. We're on the bank of the canal."

"Hey, Roger," yelled Astro from the middle of the canal, "ever see a guy make like a submarine?"

Tom and Roger sat on the top of the low bank of the canal drying off from a swim, while Astro still splashed around luxuriating in the cool water.

"Go on," yelled Roger, "let's see you drown yourself!"

"Not me, hot-shot," yelled Astro. "After that walk, all I'd have to do is open my mouth and start drinking."

Finally tiring of his sport, the big Venusian pulled himself up onto the bank of the canal and quickly dressed. Pulling on his space boots, he turned to Tom and Roger, who were breaking out the last two containers of food.

"You know, Astro," said Roger quietly, "I'll never be able to repay you for carrying me."

Tom was quiet for a moment, and then added, "Same here, Astro."

Astro grinned from ear to ear. "Answer me this one question, both of you. Would you have done it for me?"

The two boys nodded.

"Then you paid me. As long as I know I'm backed up by two guys like you, then I'm paid. Carrying you, Roger, was just something I could do for you at that particular time. One of these days, when we get out of this oven, there'll come a time when you or Tom will do something for me—and that's the way it should be."

"Thanks, Astro," said Roger. He reached over and put his hand on top of Astro's, and then Tom placed his hand on top of theirs. The three boys were quiet for a moment. There was an understanding in each of them that they had accomplished more than just survival in a desert. They had learned to respect each other. They were a unit at last.

"What do we do next?" asked Roger.

"Start walking that way," said Tom, pointing to his left along the bank of the canal that stretched off in a straight line to the very horizon. "If we're lucky, we might be able to find something to use as a raft and then we can ride."

"Think there are any fish in this canal?" asked Astro, gazing out over the cool blue water.

"Doubt it. At least I've never heard of there being any," replied Tom.

"Well," said Roger, standing up, "you can go a lot farther without food than you can without water. And we still have that big container of ham left."

"Yeah, as soon as it gets hot, we just swim instead of walk," said Astro. "And, believe me, there's going to be a lot of swimming done!"

"Think we might strike anything down that way," asked Roger. He looked down the canal in the direction Tom had indicated.

"That's the direction of the nearest atmosphere booster station. At least that was the way it looked on the chart. All of them were built near the canals."

"How far away do you think it is?" asked Astro.

"Must be at least three hundred miles."

"Let's start moving," said Roger, "and hope we can find something that'll float us on the canal."

Single file, wearing the space cloths once more as protection against the sun, they walked along the bank of the canal. When the heat became unbearable, they dipped the squares of space cloths into the water and wrapped themselves in them. When they began to dry out, they would repeat the process. At noon, when the sun dried the fabric nearly as fast as they could wet it, they stopped and slipped over the edge of the bank into the cool water. Covering their heads with the cloths they remained partly submerged until the late afternoon. When the sun had lost some of its power, again they climbed out and continued walking.

Marching late into the night, they made camp beside the canal, finished the last container of food, and, for the first time since leaving the ship, slept during the night. By the time Deimos had risen in the sky, they were sound asleep.