I saw, in the instant before my optic nerve overloaded and went out, the dim symbols of a pattern in the matrix; then I went blind and deaf in that instant of overload that is always terrifying.

Gradually, without external senses, I found orientation in the screen. My mind, extended to astronomical proportions, swept incredible distances; traversed, in fractional seconds, whole parsecs and galaxies of subjective spacetime. There came vague touches of consciousness, fragments of thought, emotions that floated like shadows — the flotsam of the mental universe.

Then, before I felt contact, I saw the white-hot flare in the screen. Somewhere another mind had fitted into the pattern. We had cast it out through time and space, like a net, and when we met a mind that fitted, it had been snared.

I swung out, bodiless, divided into a billion subjective fragments, extended over a vast gulf of spacetime. If anything happened, I would never get back into my body, but would float in the spacetime curve forever.

With infinite caution, I poured myself into the alien mind. There was a short but terrible struggle; it was embedded, enlaced in mine. The world was a holocaust of molten-glass fire and color. The air writhed with cold flames, and the glow on the screen was a shadow and then a clearing darkness and then an image, captive in my mind, and then-Light tore at my eyes. A ripping shock slammed through my brain, the floor seemed to rock and the walls to crash together and apart, and Callina was flung, reeling, against me as the energons seared the air and my brain.

Half stunned, but conscious, I looked up at Callina. The alien mind was torn free of mine. The screen was blank.

And in a crumpled heap on the floor, at the base of the Screen, where she had fallen, lay a slender, dark-haired girl.

Unsteadily, Callina knelt beside the crumpled form. I followed slowly, and bent over beside her.

“She isn’t dead?”

“Of course not.” Callina looked up. “But that was terrible, even for us. What do you think it was like for her? She’s in shock.”

The girl was lying on her side, one arm across her face.

Soft brown hair, falling forward, hid her features. I brushed it lightly back — then stopped, my hand still touching her cheek, in dazed bewilderment.

“It’s Linnell,” Callina choked. “Linnell!”

Lying on the cold floor was the girl on the spaceport; the girl I had seen in my first confused moments in Thendara.

For a moment, even knowing as I did what had happened, I thought my mind would give way. The transition had taken its toll of me, too. Every nerve in my body ached.

“What have we done?” Callina moaned. “What have we done?”

I held her tight. Of course, I thought; of course. Linnell was near; she was close to both of us; we had both been talking, and thinking of Linnell tonight. And yet…

“You know Cherillys’ two point law?” I tried to put it into simple words. “Everything, everywhere, except a matrix, exists in one exact duplicate. This chair, my cloak, the screwdriver on your table, the public fountain in Port Chicago — everything in the universe exists in one exact molecular duplicate. Nothing is unique except a matrix; but there are no three things alike in the universe.”

“Then this is — Linnell’s twin?”

“More than that. Only once in a million years or so would duplicates also be twins. This is her real twin. Same fingerprints. Same retinal eye patterns. Same betagraphs and blood type. She won’t be much like Linnell in personality, probably, because the duplicates of Linnell’s environment are scattered all over the galaxy. But in flesh and blood, they’re identical. Even her chromosomes are identical with Linnell’s.

I took up the girl’s wrist and turned it over. The curious matrix mark of the Comyn was duplicated there. “Birthmark,” I said, “but the effect is identical in her flesh. See?”

I stood up. Callina stared and stared. “Can she live in this environment, then?”

“Why not? If she’s Linnell’s duplicate, she breathes oxygen in the same ratio we do, and her internal organs are adjusted to about the same gravity.”

“Can you carry her? She’ll get another bad shock if she wakes up in this place!” Callina indicated the matrix equipment.

I grinned humorlessly.- “She’ll get one anyway.” But I managed to scoop her up, one-armed. She was frail and light, like Linnell. Callina held curtains aside for me, showed me where to lay her. I covered the girl, for it was cold, and Callina murmured, “I wonder where she comes from?”

“She was born on a world with gravity about the same as Darkover, which narrows it considerably. Vialles, Wolf, even Terra. Or, of course, some planet we never heard of.” Her speech had impressed me as Terran; but I hadn’t told Callina about that episode on the spaceport, and didn’t intend to. “Let’s leave her to sleep off the shock, and get some sleep Ourselves.”

Callina stood in the door with me, her hands locked on mine. She looked haggard and worn, but lovely to me after the shared danger, shared weariness. I bent and kissed her.

“Callina,” I whispered. It was half a question, but she freed her hand gently and I did not press her. She was right. We were both desperately exhausted. It would have been raving insanity. I put her gently away and went out without looking back. It was raining hard, but until the wet red morning rose sunlessly over Thendara I paced the courtyard, restless, and the drops on my face were not all rain.

Toward dawn I fought back to self-control, and went back to the Keeper’s Tower. I was afraid that without Callina at my side I would not find a way into the blue-ice room, or that Ashara had vanished into some inaccessible place. But she was there; and such was the illusion of the frosty light, or of my tired eyes, that she seemed younger, less guarded; like a strange, icy, inhuman Callina. My brain almost refused to think clearly, but I finally managed to formulate my plea.

“You can see — time. Tell me. The child Dyan calls mine—”

“It is yours,” Ashara said.

“Who—”

“I know. You’ve been celibate, except for Diotima Ridenow Comyn, since your Marjorie died.” She looked right through my astonished stare. “No, I didn’t read your mind, I thought the Ridenow girl might be suitable to train as I — as I trained Callina. She was not. I’m not concerned with your moralities or Diotima’s; it’s a matter of physical nerve alignments.” She went on, passionlessly, “Hastur would not accept the bare word of those who brought the child; so he brought her to my keeping for search. She is here in the Tower. You may see her. She is yours. Come with me.”

To my surprise — I don’t know why, but somehow I had felt that Ashara could not leave her strange blue-ice room-she led me through another of the bewildering blue doors and into a plain circular room. One of the furry nonhuman mutes — the servants of the Keeper’s Tower — scurried away on noiseless padded feet.

In the cool normal light Ashara’s flickering figure was colorless, almost invisible. I wondered; was it the sorceress herself, or merely a projection she wanted me to see? The room was simply furnished, and on a narrow white cot at the center, a little girl lay fast asleep. Pale reddish-gold hair lay scattered on the pillow.

I went slowly to the child, and looked down. She was very small; five or six, maybe younger. And as I looked down I knew they had told the truth. In ways impossible to explain, except to a telepath and an Alton, I knew; this was my own child, born of my own seed. The tiny triangular face bore not the slightest resemblance to my own; but my blood knew. Not my father’s. Not my brother’s. My own. My flesh.

“Who was her mother?” I asked softly.