They calculated the elements of its orbit last April. They've done it twenty times since, and every time the projected orbit is different. Just a little at first, but last week the accursed thing actually took a sudden turn, as though it were a spaceship."
The girls stared at me. "What does that mean?" Anita asked.
"They're beginning to make wild guesses but we won't go into that."
"What else is mysterious?" Venza demanded.
"The thing isn't normally visible."
Venza shifted her silk-sheathed legs. "Don't talk in code!"
"Not normally visible," I repeated. "A world one-fifth as large as the Moon could be seen plainly by our 'scopes when well beyond Pluto. It's now between Jupiter and Mars, invisible to the naked eye, of course, but still it's not very far away. I've been out there myself. With instruments, we ought to be able to see its surface; see whether it has land and water, inhabitants perhaps. You should be able to distinguish an object on its surface as large as a city, but you can't."
"Why not?" asked Anita. "Are the clouds too thick? What causes it?"
"They don't even know that," I retorted. "There is something abnormal about the light-waves coming from it. Not exactly blurred, but a distortion, a fading. It's some abnormality of the light-waves."
A swift rapping on our door-grid interrupted me, and Snap Dean burst in.
"Hola-lo, everybody! Is it a conference? You look so solemn."
He dashed across the room, kissed Venza, pretended that he was about to kiss Anita, and winked at me. He was a dynamic little fellow, small, wiry, red-headed and freckle-faced, and had been the radio-helio operator of the ill-fated Planetara. He was a perfect match for Venza, for all the millions of miles that separated their native lands. Venza, too was small and slim, her manner as readily jocular as his.
"And where have you been?" Venza demanded.
"Me? My private life is my own, so far. We're not married yet, since you insist on us going to Grebhar for the ceremony."
"Do stop it," protested Anita. "We've been talking of...."
"I know very well what you've been talking about. Everybody is. I've got news for you, Gregg." He went abruptly solemn and lowered his voice. "Halsey wants to see us, right away."
I regarded him blankly and my mind swept back. No more than a few short weeks ago Detective-Colonel Halsey of Divisional Headquarters here in Greater New York had sent for us, and we had been precipitated into the Grantline affair. "Halsey!" I burst out.
"Easy, Gregg." Snap cast a vague look around Anita's draped apartment. An open window was beside us, leading to a tiny catwalk balcony. It was moonlit now, and two hundred feet above the pedestrian viaduct.
But Snap continued to frown. "Easy, I tell you. Why shout about Halsey? The air can have ears."
Venza moved and closed and sealed the window.
"What is it?" I asked, more softly.
But Snap was not satisfied. "Anita, do you have a complete isolation barrage for this room?"
"Of course I haven't, Snap."
"Well, Gregg do you have a detector with you?"
I had none. Snap produced his little coil and indicator dial. "It's out of order, but let's see now. Shove over that chair, Gregg."
He disconnected one of the room's tube-lights and contacted with the cathode. It was a makeshift method, but as he dropped to the floor, uncoiling a little length of his wire for an external pick-up, we saw that the thing worked. The pointer on the dial-face was swaying.
"Gregg!" he muttered. "Look at that. Didn't I tell you?"
The pointer quivered in positive reaction. An eavesdropping ray was upon us.
Anita gasped, "I had no idea!"
"No, but I did." Snap added softly. "No one very close."
He and I carried the detector to the length of the hall. The indicator went nearer normal. "It must be the other way," I whispered.
We went to the moonlit balcony. "Way down there on the pedestrian arcade," I said.
"We'll soon fix that," Snap said.
Inside the room, we made connection with a newscaster's blaring voice. Under cover of it we could talk. Snap gathered us close around him.
"Halsey has something important, and it's about this interstellar invader. It all connects. His office paged me on a public mirror. I happened to see it at Park-Circle 40. When I answered it, Halsey's man wanted me to talk in code. I can't talk in code; I have enough to worry about with the interplanetary helios. Then they sent me to an official booth, where I got examined for positive legal identification, and then they put me on the official split-wave length. After all of which precautions I was told to be at Halsey's office tonight at midnight, and told a few other things."
"What?" demanded Venza breathlessly.
"Only hints. Why take chances, by repeating them now?"
"You said he wants me, too?" I put in.
"Yes. You and Venza. We've got to get into his office secretly, by the vacuum cylinders. We're to meet a man from his office at the Eighth Postal switch-station."
"Venza?" Anita said sharply. "What in the universe can he want with Venza? If she's going, I'm going too!"
Snap gazed at her and grinned. "That sounds like a logical deduction. Naturally he must want you; that's why he said Venza."
"I'm going," Anita insisted.
We left half an hour before midnight. The girls were both in gray, with long capes. We took the public monorail into the mid-Manhattan section under the city roof of the business district, and into the Eighth Postal switch-station where the sleek bronze cylinders came tumbling out of the vacuum ports to be re-routed and dispatched again.
A man was on the lookout for us. "Daniel Dean and party?"
"Yes. We were ordered here."
The detective gazed at the girls and at me. "It was three, Dean."
"And now it's four," said Snap cheerfully. "The extra one is Miss Anita Prince. Ever heard of her?"
He had indeed. "All right," he said. "If you and Haljan say so."
We were put into one of the oversized mail cylinders and routed through the tubes like sacks of recorded letters; in ten minutes, with a thump that knocked the breath out of all of us, we were in the switch-rack of Halsey's outer office.
We clambered from the cylinder. Our guide led us down one of the gloomy metal corridors. It echoed with our tread.
A door lifted.
"Daniel Dean and party."
The guard stood aside. "Come in."
The door slid down behind us. We advanced into the small blue-lit apartment, steel-lined like a vault.
1. See "Brigands of the Moon", Ace Book, D-324
CHAPTER II.
Colonel Halsey sat at his desk, with a few papers before him and a bank of instrument controls at his elbow. He pushed his audiphone and mirror-grid to one side.
"Sit down, please." He gave us each the benefit of a welcoming smile, and his gaze finished upon Anita.
"I came because you sent for Venza," Anita said quickly. "Please, Colonel Halsey, let me stay. I thought, whatever you want her for, you might need me, too."
"Quite