The Nevian physician directed his key tube upon the transparent wall of the chamber and an opening appeared, an opening which vanished as soon as he had stepped through it; Costigan kicked a valve open; and from various innocent tubes there belched forth into the water of the central lagoon and into the air over it a flood of deadly vapor. As the Nevian turned toward the prisoner there was an almost inaudible hiss and a tiny jet of the frightful, outlawed stuff struck his open gills, just below his huge, conical head. He tensed momentarily, twitched convulsively just once, and fell motionless to the floor. And outside, the streams of avidly soluble liquefied gas rushed out into air and into water. It spread, dissolved, and diffused with the extreme mobility which is one of its characteristics; and, as it diffused and was borne outward the Nevians in their massed hundreds died. Died not knowing what killed them, not knowing even that they died. Costigan, bitterly resentful of the inhuman treatment accorded the three and fiercely anxious for the success of his plan of escape, held his breath and, grimly alert, watched the amphibians die. When he could see no more motion anywhere he donned his gas-mask, strapped upon his back a large canister of the poison – his capacious pockets were already full of smaller containers – and two savagely exultant sentences escaped him.
“I am a poor, ignorant specimen of ape that can be let play with apparatus, am I?” he rasped, as he picked up the key tube of the specialist and opened the door of his prison. “They’ll learn now that it ain’t safe to judge by the looks of a flea how far he can jump!”
He stepped out through the opening into the water, and, burdened as he was, made shift to swim to the nearest ramp. Up it he ran, toward a main corridor. But ahead of him there was wafted a breath of dread Vee-Two, and where that breath went, went also unconsciousness – an unconsciousness which would deepen gradually into permanent oblivion save for the prompt intervention of one who possessed, not only the necessary antidote, but the equally important knowledge of exactly how to use it. Upon the floor of that corridor were strewn Nevians, who had dropped in their tracks. Past or over their bodies Costigan strode, pausing only to direct a jet of lethal vapor into whatever branching corridor or open door caught his eye. He was going to the intake of the city’s ventilation plant, and no unmasked creature dependent for life upon oxygen could bar his path. He reached the intake, tore the canister from his back, and released its full, vast volume of horrid contents into the primary air stream of the entire city.
And all throughout that doomed city Nevians dropped; quietly and without a struggle, unknowing. Busy executives dropped upon their cushioned, flat-topped desks; hurrying travelers and messengers dropped upon the floors of the corridors or relaxed in the noxious waters of the ways; lookouts and observers dropped before their flashing screens; central operators of communications dropped under the winking lights of their panels. Observers and centrals in the outlying sections of the city wondered briefly at the unwonted universal motionlessness and stagnation; then the racing taint in water and in air reached them, too, and they ceased wondering – forever.
Then through those quiet halls Costigan stalked to a certain storage room, where with all due precaution he donned his own suit of Triplanetary armor. Making an ungainly bundle of the other Solarian equipment stored there, he dragged it along behind him as he clanked back toward his prison, until he neared the dock at which was moored the Nevian space-speedster which he was determined to take. Here, he knew, was the first of many critical points. The crew of the vessel was aboard, and, with its independent air-supply, unharmed. They had weapons, were undoubtedly alarmed, and were very probably highly suspicious. They, too, had ultrabeams and might see him, but his very closeness to them would tend to protect him from ultra-beam observation.
Therefore he crouched tensely behind a buttress, staring through his spy-ray goggles, waiting for a moment when none of the Nevians would be near the entrance, but grimly resolved to act instantly should he feel any touch of a spying ultra-beam.
“Here’s where the pinch comes,” he growled to himself. “I know the combinations, but if they’re suspicious enough and act quick enough they can seal that door on me before I can get it open, and then rub me out like a blot; but . . . ah!”
The moment had arrived, before the touch of any revealing ray. He trained the key-tube, the entrance opened, and through that opening in the instant of its appearance there shot a brittle bulb of glass, whose breaking meant death. It crashed into fragments against a metallic wall and Costigan, entering the vessel, consigned its erstwhile crew one by one to the already crowded waters of the lagoon. He then leaped to the controls and drove the captured speedster through the air, to plunge it down upon the surface of the lagoon beside the door of the isolated structure which had for so long been his prison. Carefully he transferred to the vessel the motley assortment of containers of Vee-Two, and after a quick check-up to make sure that he had overlooked nothing, he shot his craft straight up into the air. Then only did he close his ultra-wave circuits and speak.
“Clio, Bradley – I got away clean, without a bit of trouble. Now I’m coming after you, Clio.” , “Oh, it’s wonderful that you got away, Conway!” the girl exclaimed. “But hadn’t you better get Captain Bradley first? Then, if anything should happen, he would be of some use, while I . . .”
“I’ll knock him into an outside loop if he does!” the captain snorted, and Costigan went on: “You won’t need to. You come first, Clio, of course. But you’re too far away for me to see you with my spy, and I don’t want to use the high-powered beam of this boat for fear of detection; so you’d better keep on talking, so that I can trace you.”
“That’s one thing I am good at!” Clio laughed in sheer relief. “If talking were music, I’d be a full brass band!” and she kept up a flow of inconsequential chatter until Costigan told her that it was no longer necessary; that he had established the line.
“Any excitement around there yet?” he asked her then.
“Nothing unusual that I can see,” she replied. “Why? Should there be some?”
“I hope not, but when I made my getaway I couldn’t kill them all, of course, and I thought maybe they might connect things up with my jail-break and tell the other cities to take steps about you two. But I guess they’re pretty well disorganized back there yet, since they can’t know who hit them, or what with, or why. I must have got about everybody that wasn’t sealed up somewhere, and it doesn’t stand to reason that those who are left can check up very closely for a while yet. But they’re nobody’s fools – they’ll certainly get conscious when I snatch you, maybe before . . . there, I see your city, I think.”
“What are you going to do?”
“Same as I did back there, if I can. Poison their primary air and all the water I can reach . . .”
“Oh, Conway!” Her voice rose to a scream. “They must know – they’re all getting out of the water and are rushing inside the buildings as fast as they possibly can!”
“I see they are,” grimly. “I’m right over you now, ‘way up. Been locating their primary intake. They’ve got a dozen ships around it, and have guards posted all along the corridors leading to it; and those guards are wearing masks! They’re clever birds, all right, those amphibians – they know what they got back there and how they got it. That changes things, girl! If we use gas here we won’t stand a chance in the world of getting old Bradley. Stand by to jump when I open that door!”
“Hurry, dear! They are coming out here after me!”
“Sure they are.” Costigan had already seen the two Nevians swimming out toward Clio’s cage, and had hurled his vessel downward in a screaming power dive.
“You’re too valuable a specimen for them to let you be gassed, but if they can get there before I do they’re traveling fools!”
He miscalculated slightly, so that instead of coming to a halt at the surface of the liquid medium the speedster struck with a crash that hurled solid masses of water for hundreds of yards. But no ordinary crash could harm that vessel’s structure, her gravity controls were not overloaded, and she shot back to the surface; gallant ship and reckless pilot alike unharmed. Costigan trained his key-tube upon the doorway of Clio’s cell, then tossed it aside.