grade of marshmallow.

  After he had been operating for a few years, there was no installation onthe face of the earth that could be considered Nipe-proof for more than afew minutes. He struck when and where he wanted and took whatever heneeded.

  It was manifestly impossible to guard against the Nipe, since no one knewwhat sort of loot might strike his fancy next, and there was therefore noway of knowing where or how he would hit next.

  Nor could he ever be found after one of his raids. They were plotted andfollowed out with diabolical accuracy and thoroughness. He struck, looted,and vanished. And wasn't seen again until his next strike.

  Colonel Mannheim, who had carefully puffed a cigar alight and smoked itthoughtfully during Stanton's recitation, dropped the remains of the cigarinto an ash receptacle. "Accurate but incomplete," he said quietly. "Youmust have made some guesses." He looked from Bart Stanton to Dr.Farnsworth. "I'd like to hear them."

  Farnsworth finished off the last of his coffee. "We've talked about it,"he admitted. "Although I must say the hypothesis Bart has come up withwould never have occurred to me. I'm still not sure I credit it, but" ...he shrugged ... "I can't say that I disbelieve it, either."

  Mannheim turned his eyes back to Stanton. His silence was a question.

  "Logically, my theory mightn't hold much water," Stanton admitted. "Butthe evidence seems to be conclusive enough to me." He got up, went over tothe coffee urn, and refilled his cup. "It seems incredible to me that thecombined intelligence and organizational ability of the UN Government isincapable of finding anything out about one single alien, no matter howcompetent he may be," he said as he returned to his seat.

  "Somehow, somewhere, someone must have gotten a line on the Nipe. He musthave a base for his operations, and someone should have found it by thistime.

  "If there is such a base, then it must be possible to blast him out of itwithout resorting to the kind of work it took to produce--me.

  "I may be faster and more sensitive and stronger than the average man, butthat doesn't mean that I have superhuman abilities to the extent that Ican do in two or three years what the combined forces of the Governmentcouldn't do in ten. Certainly you wouldn't rely too heavily on it.

  "And yet, apparently, you are.

  "To me that can only mean that you've got another ace up your sleeve. You_know_ we're going to get the Nipe before I die. You either have a sureway of tracing him or else you already know where he is.

  "Which is it?"

  Colonel Mannheim sighed. "We know where he is. We've known for six years."

  IV

  INTERLUDE

  The woman's eyes were filled with tears, for which the doctor wasprivately thankful. At least the original shock had worn off.

  "And there's nothing we can do? Nothing?" There was a slight catch in hervoice.

  "I'm afraid not. Not yet. There are research teams working on the problem,and one day ... perhaps...." Then he shook his head. "But not yet." Hepaused. "I'm sorry, Mrs. Stanton."

  The woman sat there on the comfortable chair and looked at thespecialist's diploma that hung on the doctor's wall--and yet, she didn'treally see the diploma at all. She was seeing something else--a kind ofdream that had been shattered.

  After a moment, she began to speak, her voice low and gentle, as thoughthe dream were still going on and she were half afraid she might wakenherself if she spoke too loudly.

  "Jim and I were so glad they were twins. Identical twin boys. He said--Iremember, he said, 'We ought to call 'em Ike and Mike.' And he laughed alittle when he said it, to show he didn't mean it.

  "I remember, I was propped up in the bed, the afternoon they were born,and Jim had brought me a new bed jacket, and I said I didn't need a newone because I would be going home the next day, and he said: 'Hell, kid,you don't think I'd just buy a bed jacket just for hospital use, do you?This is for breakfasts in bed, too.'

  "And that's when he said he'd seen the boys and said we ought to name themIke and Mike."

  The tears were coming down Mrs. Stanton's cheeks heavily now, and griefmade her look older than her twenty-four years, but the doctor saidnothing, letting her spill out her emotions in words.

  "We'd talked about it before, you know--as soon as the obstetrician foundout that I was going to have twins. And Jim ... Jim said that we shouldn'tname them alike unless they were identical twins or mirror twins. If theywere fraternal twins, we'd just name them as if they'd been ordinarybrothers or sisters or whatever. You know?" She looked at the doctor,pleading for understanding.

  "I know," he said.

  "And Jim was always kidding. If they were girls, he said we ought to callthem Flora and Dora, or Annie and Fanny, or maybe Susie and Floozie. Hewas always kidding about it. You know?"

  "I know," said the doctor.

  "And then, when they _were_ identical boys, he was very sensible about it.'We'll call them Martin and Bartholomew,' he said. 'Then if they want tocall themselves Mart and Bart, they can, but they won't be stuck withrhyming names if they don't want them.' Jim was very thoughtful that way,Doctor. Very thoughtful."

  She suddenly seemed to realize that she was crying, and took ahandkerchief out of her sleeve to dab at her eyes and face.

  "I'll have to quit crying," she said, trying to sound brave and strong."After all, it could have been worse, couldn't it? I mean, the radiationcould have killed my boys, too. Jim's dead, yes, and I've got to get usedto that. But I still have two boys to take care of, and they'll need me."

  "Yes, Mrs. Stanton, they will," said the doctor. "They'll both need you.And you'll have to be very gentle and very careful with both of them."

  "How ... how do you mean that?" she asked.

  * * * * *

  The doctor settled back in his chair and chose his words carefully."Identical twins tend to identify with each other, Mrs. Stanton. There isa great deal of empathy between people who are not only of the same age,but genetically identical. If they were both healthy, there would be verylittle trouble in their education at home or at school. Any of thestandard texts on psychodynamics in education will show you the pitfallsto avoid when dealing with identical siblings.

  "But these boys are no longer identical. One is normal, healthy, andlively. The other is ... well, as you have seen, he is slow, sluggish, andbadly co-ordinated. That condition may improve with time, but, until weknow more about such damage than we do now, he will be an invalid."

  "That's the trouble with radiation damage, Mrs. Stanton. Even when we cansave the victim's life, we cannot always save his health.

  "You can see, I think, what sort of psychic disturbances this can bringabout in such a pair. The ill boy tends to identify with the well one and,unfortunately, the reverse is true. If they are not properly handledduring their formative years, Mrs. Stanton, both can be badly damagedemotionally."

  "I ... I think I understand," the woman said. "But what sort of thingshould I look out for?"

  "I suggest that you get a good man in psychic development," the doctorsaid. "I'd hesitate to prescribe. It's out of my field. But, in general,most of your trouble will be caused by a tendency for the pair to swinginto one of two extremes.

  "Mutual antagonism can arise if one becomes jealous of the other's health,while the healthy one becomes jealous of the extra consideration shown hiscrippled brother.

  "Or, on the other hand, the healthy boy may identify so closely with hisbrother that he feels every hurt or slight, real or imagined. He becomesover-solicitous, over-protective. At the same time, the other brother maycome to depend completely on the healthy twin.

  "In both these situations, there is a positive feedback which constantlyworsens the situation. It requires a great deal of careful observation andcareful application of the proper educational stimuli to keep thesituation from developing toward either extreme. You'll need expert help,if you want both boys to display the full abilities of which they arepotentially capable."

  "I see. Could you give me the name of a
good man, Doctor?"

  The doctor nodded and picked up a book on his desk. "I'll give you severalnames. You can pick the one you like. They're all good men. There are manygood women in the field, too, but in this case, I think a man would bebest. Of course, if one of them thinks a woman is indicated, that's up tohim. As I said, that isn't my field."

  He opened the small book and riffled through it to find the names hewanted.

  V

  The image of the Nipe on the glowing screen was clear and finely detailed.It was, Bart