catalyst plants."

For a second Nikkia stared at the screen, then snapped the switch wordlessly.

The attackers seemed to have broken down the capital's defenses. Here and there, through the thick, greasy fog, a lurid red glow would take life. That was the fog-diffused reflection of a heat-beam, probing the sky for the "teardrops." After a little while the glow would flare up and as suddenly die down, followed by utter blackness. Another heat-beam out of commission.

Nikkia was frantically polling all of the city's defense commanders. They reported failure with monotonous regularity. The electronic barrage wall around the city had been passed easily—the equipment wrecked. A proton bombardment had yielded exactly nothing—He snapped the switch, peered eagerly at the mist curtain overhead—there was a series of heavy concussions. The glowing visitors were being bombarded from above. The screen glowed again....

"... but the bombs are all detonated long before they get in effective range of...."

Close by a vague shape—a darker shadow in the muggy air, suddenly materialized. It was falling swiftly—a familiar cylindrical shape with rounded ends—one of the Jovian guard ships. It struck scarcely a hundred yards from the palace—struck with a jarring burst of sound like rending metal. Then utter silence again, and darkness. No cry of wounded man. No man could survive that fall and live.

"Some kind of emanation—shields them from all known attack—" Nikkia swore monotonously and regularly.

The glowing ships now settled down to the real purpose of their attack. They began to course back and forth across the city, methodically. Like burning meteors they disappeared over the horizon, to the city's farthest suburbs, back again, as if over a measured and marked course.

And like burning, melting meteorites, they shed trails of sparks, blazing liquid. Wherever these fiery drops landed there ensued immediately a dry crackling, followed by the rattle of falling masonry. As none of the buildings were inflammable, there was no danger of fire. But wherever this incendiary trail fell, stone cracked and crumbled.

"They are destroying us! Forty million people live here in Rubio. They will kill us all, women and children too!"

"Who are they?" Sine asked suddenly.

Nikkia looked at him bleakly. "Who? Why, the Mugs, of course! Those we banished. Those we thought we wiped out."

"Oh, yeh." Sine's intonation was very dry. "They're giving you a dose of your own medicine."

Nikkia did not reply. As if he apprehended, too late, that his statement might have sounded like a plea for help, he shrugged his massive shoulders with elaborate indifference, saying;

"I and my wives are not afraid to die!"

The Earthmen could no longer watch this ruthless destruction, however, regardless of the provocation.

"You say that pink light is a protection against every known mode of attack?" Sine asked, turning sharply to the governor.

"Yes. And that's sufficient, isn't it?"

"Is it proof against this?" Sine jerked the little tube out of its clip, directed it against a stone parapet that loomed grotesquely through the fog. A brilliant white beam leaped forth, cutting the fog like a bar of platinum. Then there was darkness, and the governor, examining the parapet, noted with growing hope that a stone pillar, a foot in diameter, had been cut off smoothly, cleanly.

"The disintegrating ray!" he murmured. "I have read of that, in fiction. But here! Here it is!"

Suddenly he was all energy.

"Will you use this weapon against our enemies? I assure you that you will be well rewarded. As much eka-iodine as your ship will carry! My own ship is here, in the courtyard. It is swift, and powerful. You have already learned the controls. Take it. Bring down those murderers!"

The fiery meteor was coming toward them again, planting a swath of death a hundred yards wide. There was really only one answer possible. The terrestrial scientists, having come on a mission of peace and discovery, stepped forward in unison.

"Give me the activator key!" Sine said crisply. "Lents, will you see that the port gaskets are loose? Kass, I'd like to have you take the controls."

"Right! Right!" They ran past the governor of the greatest planet in the solar system, ignoring him, down the broad stairs, through halls of weighty magnificence, and into the rain-sluiced courtyard.

The governor's ship was waiting there. Not very large, but fine. Its polished metal gleamed richly.

"Quick, inside!" Sine threw open the manport valves. They were inside. The gravity buttons glowed with their peculiarly material lavender light, and the ship rose vertically with swift acceleration.

From the sky the death trails left by the invaders were clearly visible through the murk which obscured everything else—a pink, pulsating light. And the three glowing vessels were coming toward them.

"Get above them, Kass!" Sine commanded. "When they pass under I'll let them have it."

Closer and closer they came, those blobs of light. The Earthmen could see nothing but the light—get no hint of their construction. But that there were men inside they never doubted. The glowing ships seemed to swell, to expand monstrously, and their throbbing emanations became more furious. They seemed to hesitate as they were about to pass beneath.

"They see us?" Lents rumbled, pulling at his toga nervously. The cloth was soaked, clinging to his fat body.

"Close enough!" Sine decided, leaning out of a port, disintegrator ray tube in his hand.

At that instant the strange pink light seemed to encompass the whole planet. They were bathed in it. The fog was a sea of baleful pink. Sine stiffened into impotent rigidity. The ray tube fell from his numbed fingers. He felt himself floating, weightless, in a sea of red that smothered him deliciously. And swiftly even that consciousness was succeeded by black oblivion.

CHAPTER IV

The Monstrosities

"He's coming out of it. Hand me the water, Lents."

Sine awoke to see Kass bending over him. He felt weak and languid, and the memory of recent events was returning only slowly. He looked around, saw that he was lying in a chamber about fifteen feet square, evidently hewn out of solid rock.

"Are you all right, Sine? Answer me, boy!" Kass' bald head gleamed in the yellowish light of a single emanation tablet on the ceiling.

"I'm all right. Where are we?"

"Under the sea. Some hidden city of the Second Race—those that were banished. We are prisoners, but honored prisoners it seems."

Sine passed his hand over his eyes.

"How did we get here?"

"Some kind of emanation of theirs—the brightening of that light, I guess. It had a paralyzing effect. I know I froze where I stood, unable to move a step. And I was protected by the hull. Same with Lents. But you had your head out of the port—caught the full effect. It laid you out cold."

"They boarded us then," the fat man supplied.

"As easy as that! Simply boarded us, herded me and Lents into their own ship, which is just as suitable for navigating in water as in air. As for you, they had to carry you."

"Better tell him what to expect," Lents suggested.

Kass explained, with considerable scientific interest:

"The First Race was not so far wrong in calling them 'terrible people.' They are, a race of monstrosities. Men with four or six arms, men with hair like fur all over their bodies. With heads ten times too large. With boneless tentacles instead of limbs. With scales instead of skin. Quite horrible. And yet, most of them are highly intelligent, with normal human emotions, and painfully conscious of their deformities."

"I don't quite understand." Sine was flexing his muscles, sitting up with the support of one elbow. He saw he was lying on a pallet of dried sea weed.