Radius of insanity was Jennifer's term for it, but she had no trouble following Aissur Aissur Rus. She looked up at him. He was staring away from her, staring at an empty spot a meter or so in front of the end of his muzzle. His gaze held enough intensity to make her shiver. She used once more the standard question she'd learned as a trader. "May I speak without causing offense through ignorance of your customs?"

Aissur Aissur Rus needed a moment to return to himself. Then he said, "Speak."

"Just?a feeling I had. Were you ever on the fringes of the radius of doom?"

His big, rather ursine head swung quickly toward her. "It is so. How could you have deduced it?"

"You used the comparison you made as if you understood exactly what it entailed."

Getting a Foitan from Odern to show alarm was not easy. Jennifer had seen that. Now she saw one who was alarmed and did not try to hide it. Aissur Aissur Rus's plushy blue fur rose till he looked even bigger than he was. He bared his teeth in a way different from, and more frightening than, the usual Foitani frown-equivalent. His eyes opened so wide that Jennifer saw they really did have a pale rim.

He paced up and down the chamber, working hard to bring himself back under control. At last he turned back toward Jennifer and said, "May I never have such an experience again. I knew the danger, but proved to be unfortunate. Most of us may safely work at a distance within my personal radius of doom. I went to discuss some instrument readings with a technician and found myself?"

He stopped. His fur stood on end again. He waited until it had subsided before he went on, "I found myself filled with insight such as I'd never had before. I knew?I could feel that I knew?exactly how to comprehend the Great Unknown. I started to go toward it, to implement my knowledge. I went by the most direct route. I threw a desk and table out of the way, tried to batter down a wall at a place where no door existed in it, kicked and clawed the technician when he had the ill luck to stand in my way. It took four of his fellows at the installation to cart me back to a safe distance, and I fought them at every step until my mind was free of the Great Unknown's thrall."

The account of his episode of insanity was all the more chilling because it came out in the translator's flat tones. Jennifer shivered. She bore Aissur Aissur Rus no great goodwill, particularly as he'd evidently been the one who instigated her kidnapping. But she would not have wished on anyone what the Great Unknown did to Foitani.

She asked, "When you were safe again, did you recall the insight you'd had within your radius of doom?"

"No, and that may be the worst of it. I still feel that if I returned there, I would know again; I gather others of my kind have had a similar reaction. But none ever succeeded in communicating this knowledge, and I doubt I would prove the lone exception." He whispered something in his own language. The translator made it come out as emotionlessly as everything else, but Jennifer supplied the exclamation point: "Oh, to be wrong!"

They went to see Pawasar Pawasar Ras, who fixed Aissur Aissur Rus with a black ball-bearing stare. "You have been advocating this course for some time."

"Yes, honored kin-group leader, I have," Aissur Aissur Rus said.

Pawasar Pawasar Ras turned to Jennifer. "Why do you take his part?"

"Because if you really do want answers about the Great Unknown and nothing you've tried has worked, then you'd better try something else. If you're not serious about this project, then you can go on doing the same old things for the next twenty-eight thousand years." She threw in the number with malice aforethought. Beside her, Aissur Aissur Rus's ears twitched, but he kept quiet. She finished, "Honored kin-group leader, you were serious enough about what your people are doing here on Gilver to come here yourself. The Foitani from Rof Golan seem serious about this place, too. So why won't you do what plainly needs doing?"

Pawasar Pawasar Ras bared his teeth at her. She stood firm, as she had with Dargnil Dargnil Lin in the library. Finally Pawasar Pawasar Ras said, "Had the Great Ones encountered your species, human Jennifer, they would have made a point of exterminating it. I must say I feel a certain sympathy toward such an attitude myself."

"I'll take that for a compliment," Jennifer answered coolly. Aissur Aissur Rus's ears twitched again. Now it was Jennifer's turn to try to stare down Pawasar Pawasar Ras. "Are you going to do what needs doing, or is this whole project just a sham?"

"Honored kin-group leader, what the human means is that?" Aissur Aissur Rus began.

"Don't soften what I said," Jennifer interrupted. "I meant it. If your people were willing to invade human space to snatch me to investigate this thing, why aren't you willing to do a proper job?"

"As we have noted, you do not think kindly of our species," Pawasar Pawasar Ras said. "Tell me this, then: Why do you care whether our project succeeds or fails? Indeed, I would expect you to hope we fail, so that you might gain a measure of revenge thereby."

Jennifer looked at the big, blue alien with the same reluctant respect she'd had to give him after they first met at the Odern spaceport. "You know which questions to ask, I must say. When your people first kidnapped me, I did hope you'd fail," she answered honestly. "I've changed my mind, though, for two reasons. First, digging out the answers you need looks like the only way I'm going to get back to Saugus. And second, I just flat-out hate the idea of any job being done poorly when it could be done right."

"At last, human Jennifer, you have found a characteristic the two of us share," Pawasar Pawasar Ras said. "Very well, then, it shall be as you suggest. We shall undertake to open the tower that is the centerpiece of the Great Unknown. Should matters not go as you hope, however, remember that a share of the responsibility remains yours even if, as kin-group leader, I make the ultimate command decision here."

"You sound as if you expect the tower'll start spitting out warriors from the age of the Great Ones, or something like that," Jennifer said. "For heaven's sake, it's been sitting here ever since the Suicide Wars."

"As you did, I will give two reasons for my concern, human Jennifer," Pawasar Pawasar Ras said. "First, the Great Ones built to last, as witness the hyperdrive trap that nearly took us all on our journey here. And second, the Great Unknown remains active at least in some measure, as witness its state of preservation and the radius of doom that surrounds it. Opening the tower will be in the way of an experiment, and in a proper experiment one learns what one had not known before. I will not deny my fear at some of the things the Great Unknown may teach us."

Jennifer thought about that. A line from a Middle English fantasy writer?was it Lovecraft? Howard??floated through her mind: do not call up that which you cannot put down. Maybe it was good advice.

She shook her head. If she didn't take the chance, she didn't think she'd ever see Saugus again. She was willing to take a lot of chances to get back to human space. No matter how big the tower in the middle of the Great Unknown was, she didn't think it could hold enough old-time Foitani to overrun the entire human section of the galaxy. After what Pawasar Pawasar Ras had said, she wasn't as sure of that, but she didn't think so.

"Let's go on with it," she said.

"We will need to consult with some of our soldiers," Pawasar Pawasar Ras said. "They will best be able to gauge the type and strength of explosive likely to penetrate the tower while doing the minimum amount of damage."

"Possibly Enfram Enfram Marf. He is a specialist in ordnance," Aissur Aissur Rus suggested.