Almost at once, there was a new sound—a multiple throbbing, at a quick, snarling tempo that hinted at enormous power, growing louder each second. Hradzka stiffened and drew his blaster; as he did, five more aircraft swooped over the crest of the mountain and came rushing down toward him; not aimlessly, but as though they knew exactly where he was. As they approached, the leading edges of their wings sparkled with light, branches began flying from the trees about him, and there was a loud hammering noise.

He aimed a little in front of them and began blasting. A wing flew from one of the aircraft, and it plunged downward. Another came apart in the air; a third burst into flames. The other two zoomed upward quickly. Hradzka swung his blaster after them, blasting again and again. He hit a fourth with a blast of energy, knocking it to pieces, and then the fifth was out of range. He blasted at it twice, but without effect; a hand-blaster was only good for a thousand yards at the most.

Holstering his weapon, he hurried away, following the stream and keeping under cover of trees. The last of the attacking aircraft had gone away, but the little scout-plane was still circling about, well out of blaster-range.

Once or twice, Hradzka was compelled to stay hidden for some time, not knowing the nature of the pilot\'s ability to detect him. It was during one of these waits that the next phase of the attack developed.

It began, like the last one, with a distant roar that swelled in volume until it seemed to fill the whole world. Then, fifteen or twenty thousand feet out of blaster-range, the new attackers swept into sight.

There must have been fifty of them, huge tapering things with wide-spread wings, flying in close formation, wave after V-shaped wave. He stood and stared at them, amazed; he had never imagined that such aircraft existed in the First Century. Then a high-pitched screaming sound cut through the roar of the propellers, and for an instant he saw countless small specks in the sky, falling downward.

The first bomb-salvo landed in the young pines, where he had fought against the first air attack. Great gouts of flame shot upward, and smoke, and flying earth and debris. Hradzka turned and started to run. Another salvo fell in front of him; he veered to the left and plunged on through the undergrowth. Now the bombs were falling all about him, deafening him with their thunder, shaking him with concussion. He dodged, frightened, as the trunk of a tree came crashing down beside him. Then something hit him across the back, knocking him flat. For a moment, he lay stunned, then tried to rise. As he did, a searing light filled his eyes and a wave of intolerable heat swept over him. Then darkness....

"No, Zarvas Pol," Kradzy Zago repeated. "Hradzka will not return; the \'time-machine\' was sabotaged."

"So? By you?" the soldier asked.

The scientist nodded. "I knew the purpose for which he intended it. Hradzka was not content with having enslaved a whole Solar System: he hungered to bring tyranny and serfdom to all the past and all the future as well; he wanted to be master not only of the present but of the centuries that were and were to be, as well. I never took part in politics, Zarvas Pol; I had no hand in this revolt. But I could not be party to such a crime as Hradzka contemplated when it lay within my power to prevent it."

"The machine will take him out of our space-time continuum, or back to a time when this planet was a swirling cloud of flaming gas?" Zarvas Pol asked.

Kradzy Zago shook his head. "No, the unit is not powerful enough for that. It will only take him about ten thousand years into the past. But then, when it stops, the machine will destroy itself. It may destroy Hradzka with it or he may escape. But if he does, he will be left stranded ten thousand years ago, when he can do us no harm.

"Actually, it did not operate as he imagined and there is an infinitely small chance that he could have returned to our \'time\', in any event. But I wanted to insure against even so small a chance."

"We can\'t be sure of that," Zarvas Pol objected. "He may know more about the machine than you think; enough more to build another like it. So you must build me a machine and I\'ll take back a party of volunteers and hunt him down."

"That would not be necessary, and you would only share his fate." Then, apparently changing the subject, Kradzy Zago asked: "Tell me, Zarvas Pol; have you never heard the legends of the Deadly Radiations?"

General Zarvas smiled. "Who has not? Every cadet at the Officers\' College dreams of re-discovering them, to use as a weapon, but nobody ever has. We hear these tales of how, in the early days, atomic engines and piles and fission-bombs emitted particles which were utterly deadly, which would make anything with which they came in contact deadly, which would bring a horrible death to any human being. But thes............