“Let me repeat what I said earlier. Mr. Birch is all right. In fact, unless the Peristaltic Observer finds a problem, I’d say he’s in excellent health.”

“But we came in this morning. I was finished ages ago.”

“I’m sure. Normally, the tests take less than half an hour. In Mr. Birch’s case, we discovered something rather odd — not an illness, let me reassure you of that. But something. That’s why I want to ask you about Mr. Birch’s background. Where did you first meet, and how often have you seen him since then?”

Something, but not an illness? Then what? Something to do with Sebastian’s ability to imagine cloud patterns that bad not yet happened?

Christa Matloff seemed like a down-to-earth type, not somebody who enjoyed mystery for its own sake. Jan did her best to give a concise but full answer. She suspected that it would not be enough.

Jan and Sebastian were probably not the same age, but in a sense they had been born on the same day. There must have been years of life that preceded that, two or three of them before Jan’s first memory. But for her, life began with a ride in a low-flying aircraft, cradled by a dark-skinned woman who stroked her hair and told her that everything was all right now. Sebastian was on the woman’s other side, snuggled close.

The aircraft flew in long, slow circles. Jan, staring out of the window, saw dark, cindered land and still waters. Once she caught sight of something moving, a brown-and-white form that slithered and lurched toward a rounded heap of earth. The aircraft banked, Jan saw a flash of flame, and the mottled object was gone. On the ground where the creature had been lay a black outline of ash. The woman hugged her closer. She said, to herself or to Jan or to someone else in the aircraft — Jan would never know which — “Another damned teratoma. How many of them can they be?”

Teratoma. The word meant nothing. It was not until years later that Jan understood the term and realized what must have happened. The aircraft that had rescued her and Sebastian was based at Husvik, on South Georgia Island. It had flown many thousands of kilometers, up across the equator from latitude 55 degrees south, to take part in the first post-war survey of Earth’s northern hemisphere. At the time no one in the south expected to find humans alive beyond the equator. What they feared and what they sought were the teratomas, genetically modified and monstrous forms created in the Belt and seeded on Earth by Belt ships during the final days of the Great War. Whatever they found, the survey craft were to destroy.

They had found and killed teratomas by the thousands. They had also found, and rescued, a fair number of people. The adults were left with their memories intact. Small children found alone were treated as soon as they were picked up, to obliterate their earlier memories.

It was done as an act of kindness. The months before rescue were of terror and of deadly raids from the sky. That was followed by the agonizing death of parents and siblings from drinking poisoned water, or by near-starvation and sometimes by cannibalism. Before their memories were wiped, the woman on the aircraft had asked Jan and Sebastian their names. She wrote them on tags and placed them around their wrists; then she touched the Lethe spray to their temples.

That was all they had, all they kept from the past. They were logged in upon arrival at the displaced persons’ camp in Husvik as Janeed Jannex and Sebastian Birch. It took a month to learn to respond to them.

“After that we spent just about every day together.” Jan felt cold and clammy as she recalled the time of rescue and rebirth. It was a relief to move on to the normal days of schooling and training and planning a future. She had always taken the lead in that. Sebastian seemed happy to sit and dream. If he went along with her plans, it was only because she coaxed and persuaded him.

“No long periods of separation?” Christa Matloff had listened in sympathetic silence. “What you’ve described was more than thirty years ago. You had no individual training since then,- or different schools? I’m thinking of art courses, say, that he took and you didn’t.”

“None.” That last comment sounded as though Sebastian’s cloud drawings must be involved. Jan glanced at the clock. She had talked for close to a quarter of an hour, and there was still no sign of him. “If you think that he might have picked up a disease, I’m sure I would have been exposed to it, too.”

She was really asking a question, and the other woman was smart enough to see it that way.

“It’s not a disease. In fact, I’ll be honest with you, and admit we don’t know quite what it is. I don’t want you to feel we’re making a big mystery out of nothing. Come on, and I’ll show you.”

She led Jan back the way they had come, through another door and into a room filled with CAT and PET scanners and SQUID sensors, flanked by rows of monitors. Jan, to her great relief, saw Sebastian sitting down at the far end. He was fully dressed and — typical Sebastian — quite relaxed. He caught sight of Jan and gave her a nonchalant wave.

“You’re feeling all right?” she called.

He frowned. “All right? Yeah. Getting hungry, is all. We about done?”

He addressed his question to a blue-uniformed man who was fine-tuning an image on a monitor.

“Done as we’re likely to get.” The man turned to Christa Matloff. “We’ve scanned, analyzed, recorded, and tagged. What now?”

“Did you perform the search?”

“Long ago. I can show you the structures, and I can assure you that there’s nothing like it in the data banks.”

“Did you search the full Seine?”

“No. We’d have to get special authorization, and I didn’t think I needed to.” The man turned to Sebastian. “You said you’ve never been off-Earth before?”

“Nah.”

“So it’s down on Earth, if it’s anywhere. And it’s definitely not in the Earth data banks. Do you want me to set up a full Seine search?”

“I don’t think so, not at the moment.” Christa Matloff stepped toward the monitor. “Let’s have another look at it.”

It! They kept saying “it,” but what was it?

Uninvited, Jan followed the other woman. Sebastian, uninhibited as ever, crowded forward and pushed his moon face close to the display.

“Something in the white cells,” the man said. “This is at one to a hundred thousand. See the little round structure, a tiny nodule in with the other organelles? There’s one or two of ’em in every couple of thousand white blood cells.”

The screen showed a single irregular oval. Within it, close to the cell wall, two dark spherical objects were clearly visible.

Christa Matloff stared in silence for a few seconds. “In other types of cells, too?”

“I haven’t found any.”

“Did you do DNA and RNA checks?”

“Sure. Not a sign of either one. We’re not dealing with anything bacterial or viral. There’s also no sign of interaction with the rest of the cell. They just sit there.”

“Chemical analysis?”

“Yes. That’s another reason I’m sure they’re not alive. An ultimate analysis showed eight elements present: hydrogen, nitrogen, oxygen, magnesium, silicon, potassium, manganese, and zinc. But no you-know-what.”

“No carbon?”

“Not a trace. They’re inorganic.”

“So what are they?” Christa Matloff addressed the question to everyone, but it was clear that she was not expecting an answer.

“Beats me.” The blue-uniformed man shrugged. “But we have plenty of samples, and we’ll go on looking. I can tell you one thing, nothing I’ve seen could possibly be interpreted as a carrier of disease. That’s my job, to make sure that we’re not sending dangerous pathogens to the Outer System. And of course, we had to confirm that Mr. Birch is in good health. He is. Remarkable health, considering his age is thirty-five and he says he never takes any exercise. Dr. Matloff, as far as I’m concerned he’s cleared to go.”