"Let's try to do something about that fourth coordinate," Maia suggested, rubbing her scratchy eyes.

The young navigator coughed twice and bent over. "We've already been usin' all the obvious movin' parts." Gently, delicately, he touched pieces of the sextant, until his hand stroked the eyepiece, where one normally looked to sight horizon and stars. The image ahead of them jiggered slightly, and the number in the little indicator screen shifted just a little. "Of course," he said, with another cough. "It's the depth-of-focus adjustment. Give me room, please."

Maia stepped back. Her eyes itched and she sniffed a smoky smell. Abruptly, at the exact same moment, she and Leie sneezed. They looked at each other, and for the first time in several minutes surveyed the room. The air had changed noticeably. There was a sooty, hazy quality.

Shouts came from the back. Maia turned to see the cabin boy hurry downstairs, calling and waving. Around his nose, he wore a torn strip of cloth.

"Ensign an' doctor want t'know . . . you havin' any luck?"

"That depends," Maia replied. "We're getting some exciting philosophical insights, but not many practical applications."

The boy looked puzzled by her reply, and anxious. "We're gettin' smoke, ma'am. Doc says it'll take a while, since we're below the pirates, but the good air's gonna get sucked out, in time. They may attack before that, when it gets hard to see."

Maia had figured as much, from the evidence stinging her nose and lungs. This time she spoke earnestly. "Please tell the doctor and the ensign …" She turned to point at the forward wall — and instantly forgot what she had been about to say.

The image of the room's past was changing moment by moment. What had looked like an elegant, well-appointed lecture hall began deteriorating rapidly. First the banners and cushions vanished. Then, in a single, abrupt instant, cracks propagated across the walls. The artificial light, which had bathed the chamber until now, went out, leaving the depicted room visible only by a strange, luminous glow, apparently given off by the rocks themselves.

In the speeded time frame, dust could be seen settling and spreading in thin, advancing ripples, like wavelets washing ashore. Then even the dust froze in place.

"That's it," the man said, standing up. On the sextant dial, the number read,

PCR© +0000.761 SIDEREAL.

There was another .click. The display went blank for two seconds, and relit.

…. i®fina what is HiDDen …

Maia exhaled a tense breath. She had half expected, when the simulation caught up to its "present," to come face to face with images of themselves, staring back as if from a mirror. But the room ahead of them lay dark and empty. "It won't go any farther forward, in case you're wondering," the navigator said, with a note of disappointment.

Leie coughed. "This is all very interesting. But how's it helping us get out of here?"

Maia's lips pressed together. "I'm thinking!"

She glanced back and saw that the messenger boy had departed. The haze, which had already lessened visibility, caused things to get even worse when scratchiness in her eyes triggered the nictitating inner lids. From the hallway, she overheard harsh coughs and frantic mutterings.

Are they planning to charge out of here? It may come to that, if the reavers are willing to wait us out.

But if the smoke and heat were bad here, they would be worse upstairs, and the pirates' wood supply was limited. So this might be just the prelude to an attack.

Maia shook her head, trying to break out of a desolate spiral. She reached for ideas, and found none. The picture wall lay static before them, showing — if not today's desolation — then what might have been the scene when the simulation was last updated.

We could find out when that was, by using the other controls to go outside and check the stars … or, better yet, zoom over to the nearest town and read the date on a newspaper! Providing the simulation parses that finely.

Such thoughts were a sign of oxygen deprivation, she felt sure. Maia coughed, lowering her head. At least Renna ought to be all right, wherever he's gone to. Stronger still, her never-absent concern over Brod caused her to pray briefly to the Mother of All, and also to the God of Justice honored by men. Let Brod get out of this. Please let him live.

"I guess . . ." Leie wheezed behind a closed fist, "we oughta go join the boys. Help get ready … for what's next."

The air was going bad faster than Maia had expected. Visibility dropped rapidly, and breathing caused an ache in her chest. "I guess you're right," she agreed between coughs. Still, she was reluctant to leave. I can't help feeling we're close. So damn dose!

Leie held out her hand. With a grim smile, Maia turned and made a step forward to take it. When her weight came down on her left knee, however, it gave way and she fell, striking the hard stone floor beside the podium. The impact sent bolts of pain up her arms. Leie's hands were on her, solicitous, helping, and Maia knew a kind of gladness. At the end, they would be reconciled. She looked up to meet her sister's eyes, and felt refreshed by a wash of poignant love.

Refreshed? Her body bathed in a rush of welcome coolness. It wasn't psychological, she realized, but a strong physical sensation. "Do you feel that?" she asked her twin. After a moment's puzzlement, Leie nodded.

"Feel what?" the navigator said, squatting anxiously beside them. "Come on! They're calling muster for—"

"Quiet!" Leie hissed. "Where's it coming from?" She began crawling, casting left and right, searching for the source of the soft breeze. "It's over here!"

Helped by the man, Maia followed on eager instinct, for by now there was no other supply of good air. It seemed to come from a crack where the many-ton podium met the semicircular platform. A thin breeze emanated from that narrow passage, though it would never have been detected except under present circumstances.

Overhead, smoke billowed. The plumes shook visibly as several rocking explosions concussed the air. The men in the hall were firing, either to repel attack or in preparation for one of their own. "Go!" Maia urged the navigator. "Make them hold on awhile longer!"

Without another word, he was on his feet and gone. "Help me up," Maia told her sister, although leaving the fresh airstream was like tearing away from life itself. Coughing, they both managed to reach the sextant. "Aim downward!" Maia gasped as Leie seized one of the measurement wheels. It was increasingly difficult to see the image of the dim room, portrayed on the magic wall. It jiggled at Leie's touch, then took a jerk upward. There was a glimpse of naked rock, some dark emptiness, a quick blaze of color, and then dark rock again.

"Don't say it!" Leie snapped, bending over to focus on one thumb and forefinger, despite her body's quivering. Maia marveled at her twin's concentrated intensity. In her own case, it was all she could do to keep from folding over and vomiting.

The picture wall jittered, shifting in fits and starts. Must break the sextant, if reavers get through, Maia reminded herself. Mustn't let 'em see the simulation … or know that the wall can come awake.

More shattering booms echoed, and there were loud cries. Had battle been joined? If so, the scene outside was appallingly sinful even to imagine . . . men against women … a Perkinite propagandist's dream come true. In fact, sex had almost nothing to do with the issues in question — crime versus law, ambition against honor. Gender was incidental, but legend would say otherwise, when and if word ever spread.

The picture jogged again. A bright wedge appeared across the upper fifth of the wall, hurtful in its brilliance. Leie grunted and tried again; the bright patch shot downward so that now the lower half of the screen blazed.