"Explosives people tend to, at least the ones who live long enough to get a handle on what they're doing," Greenberg said. He spoke into the communicator again. "This was a good test, Enfram Enfram Marf. If your figures for the column are accurate, we won't have any trouble getting inside when we try this on the Great Unknown."

Again Enfram Enfram Marf did not reply. Jennifer said, "He doesn't think anyone who's not a Foitan is worth talking to."

"That's his problem. His bosses think I'm worth talking to, and they thought you were worth kidnapping so they could talk to you. I'm not going to lose a minute of sleep worrying about what the high-and-mighty Enfram Enfram Marf thinks of me."

Jennifer was sure he meant it. She admired his detachment and wished she could share it. She asked, "How do you keep from taking what aliens say personally?"

"The same way I do with humans: I try to gauge whether the person who's talking has any idea of what he's talking about. A lot of humans are damn fools, and so are a lot of aliens, Enfram Enfram Marf included. Just because he knows his explosives, he thinks he knows everything. I don't know much, but I know he's wrong."

Jennifer grinned and clapped her hands. Greenberg gave her a curious look. She wondered how she was supposed to explain to him that his line of reasoning went back thirty-five hundred years to the Apology of Socrates.

Before she had a chance to try, the sledge speaker spoke up again. "Humans Bernard and Jennifer, this is Thegun Thegun Nug speaking. We shall have a charge ready for placement tomorrow. You will then proceed to begin exploration of the tower of the Great Unknown, relaying to us such data as you uncover."

To Jennifer's way of thinking, Thegun Thegun Nug had an unpleasant habit of assuming that everything would be exactly as he wished just because he said so. Greenberg did not let that bother him. He said, "Yes, we'll start exploring for you, Thegun Thegun Nug. We'll all learn something."

"That is the desired outcome," Thegun Thegun Nug agreed.

"What I want to learn is how to get out of here," Jennifer said. For all she knew, the mike was still open. Thegun Thegun Nug didn't answer her. She hadn't expected him to. He'd known all along how she felt.

The two sledges purred away from the Foitani research base toward the Great Unknown. Enfram Enfram Marf's new shaped-charge device sat behind Bernard Greenberg. Jennifer was glad it didn't rest on her sledge. She didn't quite trust Enfram Enfram Marf not to touch a button and say it was an accident. A meter-and-a-half hole out of her middle wouldn't leave much…

They'd only gone a couple of kilometers, barely even to the edge of the radius of doom, when a loud, warbling whistle began behind them. "What the devil is that?"

"It's a Foitani alarm," Greenberg answered.

"It sure alarms me."

Greenberg spoke into the communicator on the sledge. "Human Bernard to Foitani base: Why have you switched on your alarms?" He repeated himself several times.

For a long time?more than a minute?no answer came. Jennifer began to wonder if the Foitani had forgotten about them. Then the cool tones of the translator came over the speaker. "Humans Bernard and Jennifer, this is Pawasar Pawasar Ras. I suggest you take cover as expeditiously as possible. Gilver is once more under attack from the savages of Rof Golan. Vectors of incoming ships indicate that they may attempt to land ground forces on Gilver, most probably with a view to assaulting or capturing the Great Unknown."

"We'd better head back," Jennifer said. Fliers sprang into the sky from the Foitani base. Cloven air shouted far behind them. Missiles leaped off launchers.

Then, from nowhere, a flier shrieked overhead at treetop height. A string of what might have been finned eggs fell from its belly. Had it sought the two sledges, it would have blasted them to bits. But its target was a hardpoint a few hundred meters to the west, between the humans and the base. Explosions smote Jennifer's ears. With an instinct she didn't know she owned, she threw herself off her sledge and onto the roadway, flat on her belly.

More explosions came, some distant, some close enough to lift her off the ground and slam her back down. During one brief lull, she looked over and saw Greenberg beside her. She had no idea how or when he'd got there. Then more bombs fell. Shrapnel whispered overhead.

Greenberg put his mouth next to her ear. "We can't go back," he screamed through the din.

"We can't stay here, either," she screamed back. As if to underscore her words, a fragment of bomb casing went spaang! off the side of a sledge.

"Then we head for the Great Unknown," Greenberg said, still at the top of his lungs.

Jennifer thought it over, as well as she could think in the midst of chaos and terror. "Sounds good," she said. "Let's do it, if the bombing ever moves away from us. It's the one place on the planet where the Foitani can't come after us."

"The ones from Odern can't, anyhow," Greenberg said. "We just have to hope that holds for the ones from Rof Golan, too."

"I wish you hadn't said that," Jennifer told him. She glanced up at her sledge. "I also wish we had more kibbles and water along." They'd planned on staying at the Great Unknown for a couple of days if they succeeded in getting into the tower, so they weren't without supplies. She looked up at the plastic bag of kibbles again and fought back a laugh. She'd never imagined a day would come when she wanted more of them than she had. She'd never imagined most of the things that had happened to her since the day the Foitani walked into her class at Saugus Central University.

More bombs struck, so close that she felt the impact with her whole body much more than she heard it. She and Greenberg clutched each other, life clinging to life in the middle of mechanized death. He shouted something at her. She knew that, but she was too stunned and deafened to tell what it was. She looked at him and shook her head.

"I love you," he said again. She still could not hear him, but his lips were easy to read.

"Why are you telling me now?" she said, slowly and with exaggerated movements of her own lips so he could follow. "We're liable to get blown to bits any minute."

He nodded vehemently. "That's just why. I didn't want to die without letting you know."

"Oh." She supposed it was terribly romantic, but she needed to be able to think about it. Thought was impossible here; she was battered and deafened and more frightened than she'd ever been in her life. Holding on to him still seemed like a good idea, so she kept on doing it.

The explosions grew more distant. Jennifer detached herself from Greenberg, far enough to peer past the front of the sledge. Dirt rose in graceful fountains all around the research base. The base fought back; close-in guns chattered maniacally, blasting bombs and incoming missiles before they struck home.

"If we're ever going to move, this is probably the time to do it," she told Greenberg. "Nobody seems to be paying attention to us."

"Let's go, then," he said. "The farther inside the radius of insanity we are, the better I'll like it." They scrambled onto their sledges and sent them dashing ahead at their best?and only?forward speed. No healthy Foitan would have had the least trouble running them down.

Greenberg looked over his shoulder. "Good thing we didn't head back to the base," he said. Jennifer looked back, too. A troop-carrier had landed right about where they would have been if they'd tried to reverse their course. Foitani?presumably Foitani from Rof Golan?leaped out of it and scrambled for cover. They started firing with automatic weapons heavier than anything a human could have carried.

"I wouldn't have wanted to meet them up close, no," Jennifer admitted. Meet wasn't quite the right word, she thought. The Foitani didn't look like the sort who would have waited for formal introductions before they started shooting.