"Chee," said Murgatroyd doubtfully.
"Oh, we'll manage," Calhoun assured him. "Somehow!"
He spread out his photographs. Kim Walpole had marked where he should go and a route to it. Having been in the city while it was being built, he knew even the service lanes which, being sunken, were not a part of the city's good looks.
"But the invaders," explained Calhoun, "won't deign to use grubby service lanes. They consider themselves aristocrats because they were sent to be conquerors, though the work required of them was simple butchery. I wonder what sort of swine run the world they came from!"
He put away the photos and headed for the city again. He branched off the main highway, near the city. A turn-off descended into a cut. The road in the cut was intended for loads of agricultural produce entering the city. It was strictly utilitarian. It ran below the surface of the park areas, and entered the city without pride. When among the buildings it ran between rows of undecorated gates, behind which waste matter was destined to be collected to be carted away as fertilizer for the fields. The city was very well designed.
Rolling through the echoing sunken road, Calhoun saw, just once, a ground-car in motion on a far-flung, cobwebby bridge between two tall towers. It was high overhead. Nobody in it would be watching grubby commerce roads.
The whole affair was very simple indeed. Calhoun brought the car to a stop beneath the overhang of a balconied building many stories high. He got out and opened the gate. He drove the car into the cavernous, so-far-unused lower part of the building. He closed the gate behind him. He was in the center of the city, and his presence was unknown. This was at three or later in the afternoon.
He climbed a clean new flight of steps and came to the sections the public would use. There were glassy walls which changed their look as one moved between them. There were the lifts. Calhoun did not try to use them. He led Murgatroyd up the circular ramps which led upward in case of unthinkable emergency. He and Murgatroyd plodded up and up. Calhoun kept count.
On the fifth level there were signs of use, while all the others had that dusty cleanness of a structure which has been completed but not yet occupied.
"Here we are," said Calhoun cheerfully.
But he had his blaster in his hand when he opened the door of the laboratory. It was empty. He looked approvingly about as he hunted for the storeroom. It was a perfectly equipped biological laboratory, and it had been in use. Here the few doomed physicians awaiting the city's population had worked desperately against the plague. Calhoun saw the trays of cultures they'd made, dried up and dead now. Somebody had turned over a chair. Probably when the laboratory was searched by the invaders, in case someone not of their kind still remained alive in it.
He found the storeroom. Murgatroyd watched with bright eyes as he rummaged.
"Here we have the things men use to cure each other," said Calhoun oracularly. "Practically every one a poison save for its special use! Here's an assortment of spores—pathogenic organisms, Murgatroyd. They have their uses. And here are drugs which are synthesized nowadays, but are descended from the poisons found on the spears of savages. Great helps in medicine. And here are the anesthetics—poisons too. These are what I am counting on."
He chose, very painstakingly. Dextrethyl. Polysulfate. The one marked inflammable and dangerous. The other with the maximum permissible dose on its label, and the names of counteracting substances which would neutralize it. He burdened himself. Murgatroyd reached up a paw. Since Calhoun was carrying something, he wanted to carry something, too.
They went down the circular ramp again as sunset drew near. Calhoun searched once more in the below-surface levels of the buildings. He found what he wanted—a painter's vortex-gun which would throw "smoke rings" of tiny paint droplets at a wall or object to be painted. One could vary the size of the ring at impact from a bare inch to a three-foot spread.
Calhoun cleaned the paint-gun. He was meticulous about it. He filled its tank with dextrethyl brought down from the laboratory. He piled the empty containers out of sight.
"This trick," he observed, as he picked up the paint-gun again, "was devised to be used on a poor devil of a lunatic who carried a bomb in his pocket for protection against imaginary assassins. It would have devastated a quarter-mile circle, so he had to be handled gently."
He patted his pockets. He nodded.
"Now we go hunting—with an oversized atomizer loaded with dextrethyl. I've polysulfate and an injector to secure each specimen I knock over. Not too good, eh? But if I have to use a blaster I'll have failed."
He looked out a window at the sky. It was now late dusk. He went back to the gate to the service road. He went out and carefully closed it behind him. On foot, with many references to the photomaps, he began to find his way toward the landing grid. It ought to be something like the center of the invaders' location.
It was dark when he climbed other service stairs from the cellar of another building. This was the communications building of the city. It had been the key to the mopping-up process the invaders began on landing. Its callboard would show which apartments had communicators in use. When such a call showed, a murder party could be sent to take care of the caller. Even after the first night, some individual, isolated folk might remain, unaware of what was happening. So there would be somebody on watch, just in case a dying man called for the solace of a human voice while still he lived.
There was a man on watch. Calhoun saw a lighted room. Paint-gun ready, he moved very silently toward it. Murgatroyd padded faithfully behind him.
Outside the door, Calhoun adjusted his curious weapon. He entered. The man nodded in a chair before the lifeless board. When Calhoun entered he raised his head and yawned. He turned.
Calhoun sprayed him with smoke rings—vortex rings. But the rings were spinning missiles of vaporized dextrethyl, that anesthetic developed from ethyl chloride some two hundred years before, and not yet bettered for its special uses. One of its properties was that the faintest whiff of its vapor produced a reflex to gasp. A second property was that, like the ancient ethyl chloride, it was the quickest-acting anesthetic known.
The man by the callboard saw Calhoun. His nostrils caught the odor of dextrethyl. He gasped.
He fell unconscious.
Calhoun waited patiently until the dextrethyl was out of the way. It was almost unique among vapors in that at room temperature it was lighter than air. It rose toward the ceiling. Presently Calhoun moved forward and brought out the polysulfate injector. He bent over the unconscious man. He did not touch him otherwise.
He turned and walked out of the room with Murgatroyd piously marching behind him.
Outside, Calhoun said, "As one medical man to another, perhaps I shouldn't have done that. But I'm dealing with a health hazard, a plague. Sometimes one has to use psychology to supplement standard measures. I consider that the case here. Anyhow this man should be missed sooner than most. He has a job where his failure to act should be noticed."
"Chee?" asked Murgatroyd zestfully.
"No," said Calhoun. "He won't die. He wouldn't be so unkind."
It was dark outdoors now. When Calhoun stepped out into the street—he'd touched nothing in the callboard office to show that he'd entered it—nightfall was complete. Stars shone brightly, but the empty, unlighted ways of the city were black. There seemed to be a formless menace in the air. When Calhoun moved down the street, Murgatroyd, who hated the dark, reached up a furry paw and held on to Calhoun's hand for reassurance.