On the way back to the Med Ship, Calhoun stopped at another place where, on a grass-growing planet, there would have been green sward. There were Earth-type trees, and some native ones, and between them there should have been a lawn. The trees were thriving, but the ground-cover plants were collapsed and rotting. Calhoun picked up a bit of the semi-slime and smelled it. It had a faintly sour and astringent smell, the same he'd noticed when he opened the airlock door. He threw the stuff away and brushed off his hands. Something had killed the ground-cover plants which had the habit of killing Earth-type grass when planted here.
He listened. Everywhere that humans live, there are insects and birds and other tiny creatures which are essential parts of the ecological system to which the human race is adjusted. They have to be carried to and established upon every new world that mankind hopes to occupy. But there was no sound of such living creatures here. It was probable that the bellowing roar of the Med Ship's emergency rockets was the only real noise the city had heard since its people went away.
The stillness bothered Murgatroyd. He said, "Chee!" in a subdued tone and stayed close to Calhoun. Calhoun shook his head. Then he said abruptly:
"Come along, Murgatroyd!"
He went back to the grid and the building housing its controls. He didn't look at the space-port log this time. He went to the instruments recording the second function of a landing-grid. In addition to lifting up and letting down ships of space, a landing-grid drew down power from the ions of the upper atmosphere, and broadcast it. It provided all the energy that humans on a world could need. It was solar power, in a way, absorbed and stored by a layer of ions miles high, which then could be drawn on and distributed by the grid. During his descent Calhoun had noted that broadcast power was still available. Now he looked at what the instruments said.
The needle on the dial showing power-drain moved slowly back and forth. It was a rhythmic movement, going from maximum to minimum power-use, and then back again. Approximately six million kilowatts was being taken out of the broadcast every two seconds for half of one second. Then the drain cut off for a second and a half, and went on again—for half a second.
Frowning, Calhoun raised his eyes to a very fine color photograph on the wall above the power dials. It was a picture of the human-occupied part of Maya, taken four thousand miles out in space. It had been enlarged to four feet by six, and Maya City could be seen as an irregular group of squares and triangles measuring a little more than half an inch by three-quarters. The detail was perfect. It was possible to see perfectly straight, infinitely thin lines moving out from the city. They were multiple-lane highways, mathematically straight from one city to another, and then mathematically straight—even though at a new angle—until the next. Calhoun stared thoughtfully at them.
"The people left the city in a hurry," he told Murgatroyd, "and there was little confusion, if any. So they knew in advance that they might have to go, and were ready for it. If they took anything, they had it ready-packed in their cars. But they hadn't been sure they'd have to go because they were going about their businesses as usual. All the shops were open and people were eating in restaurants, and so on."
Murgatroyd said, "Chee!" as if in full agreement.
"Now," demanded Calhoun, "where did they go? The question's really that of where they could go! There were about eight hundred thousand people in this city. There'd be cars for everyone, of course, and two hundred thousand cars would take everybody. But that's a lot of ground-cars! Put 'em two hundred feet apart on a highway, and that's twenty-six cars to the mile on each lane . . . Run them at a hundred miles an hour on a twelve-lane road—using all lanes one way—and that's twenty-six hundred cars per lane per hour, and that's thirty-one thousand . . . Two highways make sixty-two . . . Three highways . . . With two highways they could empty the city in under three hours, and with three highways close to two . . . Since there's no sign of panic, that's what they must have done. Must have worked it out in advance, too. Maybe they'd done it before. . . ."
He searched the photograph which was so much more detailed than a map. There were mountains to the north of Maya City, but only one highway led north. There were more mountains to the west. One highway went into them, but not through. To the south there was sea, which curved around some three hundred miles from Maya City and made the human colony on Maya into a peninsula. It was a small fraction of the planet, but grains wouldn't grow there. The planet could grow native plants for raw material for organic chemicals, but it couldn't grow all its own food so its population was limited.
"They went east," said Calhoun presently. He traced lines with his finger. "Three highways go east. There's the only way they could go, quickly. They hadn't been sure they'd have to go but they knew where to go when they did. So when they got their warning, they left. On three highways, to the east. And we'll follow them and ask what the hell they ran away from. Nothing's visible here!"
He went back to the Med Ship, Murgatroyd skipping with him. As the airlock door closed behind them, he heard a click from the outside-microphone speakers. He listened. It was the doubled clicking, as of something turned on and almost at once turned off again. There was a two-second cycle—the same as that of the power-drain. Something drawing six million kilowatts went on and immediately off again every two seconds. It made a sound in speakers linked to outside microphones, but it didn't make a noise in the air. The microphone clicks were induction; pick-up; like cross-talk on defective telephone cables.
Calhoun shrugged his shoulders almost up to his ears. He went to the communicator.
"Calling Candida—" he began, and the answer almost leaped down his throat.
"Candida to Med Ship. Come in! Come in! What's happened down there?"
"The city's deserted without any sign of panic," said Calhoun, "and there's power and nothing seems to be broken down. But it's as if somebody had said, 'Everybody clear out' and they did. That doesn't happen on a whim! What's your next port of call?"
The Candida's voice told him, hopefully.
"Take a report," commanded Calhoun. "Deliver it to the public-health office immediately after you land. They'll get it to Med Service sector headquarters. I'm going to stay here and find out what's been going on."
He dictated, growing irritated as he did so because he couldn't explain what he reported. Something serious had taken place, but there was no clue as to what it was. Strictly speaking, it wasn't certainly a public-health affair. But any emergency the size of this one involved public-health factors.
"I'm remaining aground to investigate," finished Calhoun. "I will report further when or if it is possible. Message ends."
"What about our passenger?"
"To the devil with your passenger!" said Calhoun peevishly. "Do as you please!"
He cut off the communicator and prepared for activity outside the ship. Presently he and Murgatroyd went to look for transportation. The Med Ship couldn't be used for a search operation. It didn't carry enough rocket-fuel. They'd have to use a ground vehicle.
It was again shocking to note that nothing had moved but sun-shadows. Again it seemed that everybody had simply walked out of some door or other and failed to come back. Calhoun saw the windows of jewellers' shops. Treasures lay unguarded in plain view. He saw a florist's shop. Here there were Earth-type flowers apparently thriving, and some strangely beautiful flowers with olive green foliage which throve as well as the Earth-plants. There was a cage in which a plant had grown, and that plant was wilting and about to rot. But a plant that had to be grown in a cage . . .
He found a ground-car agency, perhaps for imported cars, perhaps for those built on Maya. He went in. There were cars on display. He chose one—an elaborate sports car. He turned its key and it hummed. He drove it carefully out into the empty street. Murgatroyd sat interestedly beside him.
"This is luxury, Murgatroyd," said Calhoun. "Also it's grand theft. We medical characters can't usually afford such things or have an excuse to steal them. But these are parlous times. We take a chance."
"Chee!" said Murgatroyd.
"We want to find a fugitive population and ask what they ran away from. As of the moment, it seems that they ran away from nothing. They may be pleased to know they can come back."
Murgatroyd again said, "Chee!"
Calhoun drove through vacant ways. It was somehow nerve-racking. He felt as if someone should pop out and say, "Boo!" at any instant. He discovered an elevated highway and a ramp leading up to it. It ran west to east. He drove eastward, watching sharply for any sign of life. There was none.
He was nearly out of the city when he felt the chest-impact of a sonic boom, and then heard a trailing-away growling sound which seemed to come from farther away as it died out. It was the result of something traveling faster than sound, so that the noise it made far away had to catch up with the sound it emitted nearby.
He stared up. He saw a parachute blossom as a bare speck against the blue. Then he heard the even deeper-toned roaring of a supersonic craft climbing skyward. It could be a spaceliner's lifeboat, descended into atmosphere and going out again. It was. It had left a parachute behind and now went back to space to rendezvous with its parent ship.
"That," said Calhoun impatiently, "will be the Candida's passenger. If he was insistent enough—"
He scowled. The Candida's voice had said its passenger demanded to be landed for business reasons. And Calhoun had a prejudice against some kinds of business men who would think their own affairs more important than anything else. Two standard years before, he'd made a planetary health inspection on Texia II, in another galactic sector. It was a llano planet and a single giant business enterprise. Illimitable prairies had been sown with an Earth-type grass which destroyed the native ground-cover—the reverse of the ground-cover situation here—and the entire planet was a monstrous range for beef-cattle. Dotted about were gigantic slaughter-houses, and cattle in masses of tens of thousands were shifted here and there by ground-induction fields which acted as fences. Ultimately the cattle were driven by these same induction-fences to the slaughter-houses and actually into the chutes where their throats were slit. Every imaginable fraction of a credit profit was extracted from their carcasses, and Calhoun had found it appalling. He was not sentimental about cattle, but the complete cold-bloodedness of the entire operation sickened him. The same cold-bloodedness was practiced toward the human employees who ran the place. Their living-quarters were sub-marginal. The air stank of cattle-murder. Men worked for the Texia Company or they did not work. If they did not work they did not eat. If they worked and ate—Calhoun could see nothing satisfying in being alive on a world like that! His report to Med Service had been biting. He'd been prejudiced against business men ever since.
But a parachute descended, blowing away from the city. It would land not too far from the highway he followed. And it didn't occur to Calhoun not to help the unknown chutist. He saw a small figure dangling below the chute. He slowed the ground-car. He estimated where the parachute would land.
He was off the twelve-land highway and on a feeder-road when the chute was a hundred feet high. He was racing across a field of olive-green plants—the field went all the way to the horizon—when the parachute actually touched ground. There was a considerable wind. The man in the harness bounced. He didn't know how to spill the air. The chute dragged him.
Calhoun sped ahead, swerved, and ran into the chute. He stopped the car and the chute stopped with it. He got out.
The man lay in a helpless tangle of cordage. He thrust unskillfully at it. When Calhoun came up he said suspiciously:
"Have you a knife?"
Calhoun offered a knife, politely opening its blade. The man slashed at the cords. He freed himself. There was an attaché-case lashed to his chute-harness. He cut at those cords. The attaché-case not only came clear, but opened. It dumped out an incredible mass of brand-new, tightly-packed interstellar credit certificates. Calhoun could see that the denominations were one-thousand and ten-thousand credits. The man from the chute reached under his armpit and drew out a blaster. It was not a service weapon. It was elaborate. It was practically a toy. With a dour glance at Calhoun he put it in a side pocket and gathered up the scattered money. It was an enormous sum, but he packed it back. He stood up.
"My name is Allison," he said in an authoritative voice. "Arthur Allison. I'm much obliged. Now I'll get you to take me to Maya City."
"No," said Calhoun politely. "I just left there. It's deserted. I'm not going back. There's nobody there."
"But I've important bus—" The other man stared. "It's deserted? But that's impossible!"
"Quite," agreed Calhoun, "but it's true. It's abandoned. It's uninhabited. Everybody's left it. There's none there at all."
The man who called himself Allison blinked unbelievingly. He swore. Then he raged profanely. But he was not bewildered by the news. Which, upon consideration, was itself almost bewildering. But then his eyes grew shrewd. He looked about him.
"My name is Allison," he repeated, as if there were some sort of magic in the word. "Arthur Allison. No matter what's happened, I've some business to do here. Where have the people gone? I need to find—"
"I need to find them too," said Calhoun. "I'll take you with me, if you like."
"You've heard of me." It was a statement, confidently made.
"Never," said Calhoun politely. "If you're not hurt, suppose you get in the car? I'm as anxious as you are to find out what's happened. I'm Med Service."
Allison moved toward the car.
"Med Service, eh? I don't think much of the Med Service! You people try to meddle in things that are none of your business!"
Calhoun did not answer. The muddy man, clutching the attaché-case tightly, waded through the olive-green plants to the car and climbed in. Murgatroyd said cordially: "Chee-chee!" but Allison viewed him with distaste.
"What's this?"
"He's Murgatroyd," said Calhoun. He's a tormal. He's Med Service personnel."
"I don't like beasts," said Allison coldly.
"He's much more important to me than you are," said Calhoun, "if the matter should come to a test."
Allison stared at him as if expecting him to cringe. Calhoun did not. Allison showed every sign of being an important man who expected his importance to be recognized and catered to. When Calhoun stirred impatiently he got into the car and growled a little. Calhoun took his place. The ground-car hummed. It rose on the six columns of air which took the place of wheels. It went across the field of dark-green plants, leaving the parachute deflated across a number of rows, and a trail of crushed-down plants where it had moved.
It reached the highway again. Calhoun ran the car up on the highway's shoulder, and then suddenly checked. He'd noticed something. He stopped the car and got out. Where the ploughed field ended, and before the coated surface of the highway began, there was a space where on another world one would expect to see green grass. On this planet grass did not grow. But there would normally be some sort of self-planted vegetation where there was soil and sunshine and moisture. There had been such vegetation here, but now there was only a thin, repellant mass of slimy and decaying foliage. Calhoun bent down to it. It had a sour, faintly astringent smell of decay. These were the ground-cover plants of Maya of which Calhoun had read. They had motile stems and leaves and flowers. They had cannibalistic tendencies. They were dead. But they were the local weeds which made it impossible to grow grain for human use upon this world.
Calhoun straightened up and returned to the car. Plants like this were wilted at the base of the space-port building, and on another place where there should have been sward. Calhoun had seen a large dead member of the genus in a florist's. It had been growing in a cage before it died. There was a singular coincidence, here. Humans ran away from something, and something caused the death of a particular genus of cannibal weeds.
It did not exactly add up to anything in particular, and certainly wasn't evidence for anything at all. But Calhoun drove on in a vaguely puzzled mood. The germ of a guess was forming in his mind. He couldn't pretend to himself that it was likely, but it was surely no more unlikely than most of two million human beings abandoning their homes at a moment's notice.