There was quiet save for the chorus of myriads of small voices which serenaded the heavens. It was a remarkable total sound. Now and again Calhoun heard sustained deep-bass notes, like the lowest possible tones of a great organ. Then there were liquid trillings, which might come from any kind of bird or beast or reptile. In between came chirpings and abrupt paeans of music, like woodwinds essaying tentative melodic runs.
It was easy for Calhoun to wait. The whole affair had added itself up in his mind. He felt that he not only knew what had happened on this world, but what might happen elsewhere if this particular enterprise proved profitable. Men who could arrange this could go further. Much further. What he'd imagined was trivial compared to what could come next.
There was a light in motion in the city. Calhoun sat up, all alertness, to watch it. It was a ground-car on a highway, headlights glaring to light the way before it. It vanished behind buildings. It reappeared. It crossed a far-flung bridge and vanished again, and again reappeared. It was drawing closer, and presently its lights glared in Calhoun's eyes as it sped furiously across the landing grid's turf floor, headed for the sprawling building where the transformers and the controls for the grid were housed.
There it came to a swiftly braked stop. Its light stayed on. Men jumped from it and ran into the control building. Calhoun heard no voices. The songs of the night creatures would have blotted out human voices. In minutes, though, more men came out of the building. They clustered about the ground-car. After only seconds, the car was again in motion, jouncing and bouncing over the turf toward the grounded spaceship.
It stopped within a hundred yards of where Calhoun had concealed himself. The headlights glittered and glistened against the bulging, silvery metal of the spacecraft. A man shouted at it, "Open up! Open up! Something's happened! A man's sick! It looks like the plague!"
There was no sign. He shouted again. Another man pounded on the thick metal of the airlock's outer door.
A voice spoke suddenly out of external loudspeakers. "What's this? What's the matter?"
Many voices tried to babble, but a harsh voice silence them and barked statements, every one of which Calhoun could have written down in advance. There'd been a man on watch in the city's communication center. He didn't put through calls from different places in use by the invaders. Someone went to find out why. The man at the callboard was unconscious. It looked like he had the plague. It looked like the shots he'd had to make him immune didn't work.
The voice coming over the loudspeakers said, "Nonsense! Bring him in!"
Seconds later the airlock door cracked open and descended outward, making a ramp from the ground to the cubbyhole which was the lock as now revealed. The men on the ground hauled a limp figure out of the ground-car. They half-carried and half-dragged it up the ramp into the lock. Calhoun saw the inner door open. They dragged the figure inside.
Then nothing happened, except that one man came out almost immediately, wiping his hands on his uniform as if hysterically afraid that by touching his unconscious companion he'd infected himself with the plague.
Presently another man came out. He trembled. Then the others. The harsh voice said savagely, "So he's got to find out what's the matter. It can't be the plague. We had shots against it. It's bound to be all right. Maybe he fainted or something. Stop acting like you're going to die! Go back on duty! I'll order a roll call, just in case."
Calhoun listened with satisfaction. The inner airlock door closed, but the outer one remained down as a ramp. The car trundled away, stopped and discharged some passengers at the control building, and went off into the distance. It disappeared on the highway where it had first appeared.
"The man I knocked out," he said dryly, to Murgatroyd, "impresses them unfavorably. They hope he's only an accident. We'll see. But that authoritative person is going to order a roll call. He ought to find something to bother them all, when that takes place."
"Chee," said Murgatroyd in a subdued tone.
There was again silence and stillness save for the open country song to the stars. There seemed to be occasional drumbeats in that chorus now.
It was half an hour before light showed on the ground by the control building. It was as if invisible doors had been opened, and light streamed out of them. In minutes a traveling light appeared. It vanished and was again visible, like the lights of the first car.
"Ha!" said Calhoun, gratified. "Checking up, they found the invader we left in the street. They reported it by communicator. Maybe they reported two others missing—one of whom is beside you, Murgatroyd. They ought to feel slightly upset."
The car dashed across the landing grid's center and braked. Figures waited for it. With the briefest of pauses it came again to the ship with the opened airlock door. The harsh voice panted, "Here's another one! We're bringing him in."
The loudspeaker said, somehow vexedly, "Very well. But the first man hasn't got the plague. His metabolic rate is normal. He has not got the plague!"
"Here's another one, just the same!"
The figures struggled up the ramp with a second limp burden. Minutes later they emerged again.
"He didn't get that first man awake," said an uneasy voice. "That looks bad to me."
"He says it ain't the plague."
"If he says it's not," snapped the authoritative voice, "then it's not! He ought to know. He invented the plague!"
Calhoun, behind the giant support for the landing grid, said, "Ah!" very quietly to himself.
"But—look here," said a frightened voice. "There were doctors in the city when we got here. Maybe some of 'em got away. Maybe—maybe they had some kinda germ that they've turned loose to kill us . . ."
The authoritative voice snarled. All the voices broke into a squabbling babble. The invaders were worried. They were frightened. Normally it would never have occurred to them to suspect a disease deliberately introduced among them. But they were here to follow up just such a disease. They did not understand such menaces. They'd been willing enough to profit, so long as the matter was strictly one-sided. But now it looked like some disease was striking them down. It seemed very probable that it was the plague to which they had been assured that they were immune. Some of them already had the shakes.
The car went away from the grounded spaceship. It stopped for a long time before the control building. There was agitated argument there. Calhoun heard the faint squabbling sound above the voices of the night. The car went away again.
He allowed twenty minutes to pass. They seemed very long to him. Then he picked up the man he'd knocked out, outside the room with the noisy drinking party. He heaved him over his shoulder. He'd pulled the uniform of the third of his dark-street victims over his own, and that third man lay in an areaway in his underwear. He'd be found eventually.
"We'll ask for our invitation into the ship—and the laboratory, Murgatroyd. Come along!"
He moved toward the still and silent spaceship.
It swelled and loomed enormously as he approached it. The outside lock door still lay extended downward as a ramp. He tramped on the metal incline. He went into the lock. There he banged on the inner door and called, "Here's another one! Out like the others! What'll I do with him?"
A metallic voice said angrily, "Wait!"
Calhoun waited. Two unconscious men, brought separately by a group of men who were more frightened the second time than the first, made it extremely likely that a third unconscious man would not have a group of solicitous companions with him. One man to risk the supposed contagion was very much more likely.