"Let's not be hasty," said Mendark. "We'll keep watch."

As night fell they saw a faint glow among the rubble. A luminous gas was seeping out of it, writhing and straining against its imprisonment.

"Oh!" said Malien, very disturbed. "I don't like that at all." She rubbed a dusty streak across her brow.

"It's oozed out of the Nightland. The gate is still open."

"And he's on the other side!" Yggur said. "We can't use it!"

"Is there nothing we can do?" Shand pleaded.

"Seal the Nightland!" said Yggur harshly.

"How can we? He's holding it open."

"I hate to say it," said Mendark, "but Yggur is right. The gate is trapped. We've no option but to seal it." He cast a sympathetic glance at Shand.

Tallia shuddered. She looked around the room as if sizing up her enemy. She bit her lip. "I'd-I've got to try again," she said softly.

"After that? You won't!" Mendark snapped.

"How can we leave them there?" she asked. Having abandoned Karan once, she could not think of doing it again. "I'm prepared to risk my life."

"I'm not! It can't be done."

"Mendark-"

Mendark smashed his fist down on the dome. "The whole world is at stake, Tallia!"

"And I can't help thinking that you want it for yourself," she said, suddenly furious.

"I stand on my record, ever since Rulke was first put away."

"And you never stop talking about it," Tallia retorted. "Let posterity be the judge of your worth."

"I will, never doubt it!" he cried.

"I can't sacrifice them," Tallia said stubbornly.

"Pah! Then you will never be Magister after me."

"I don't want it, if it means that I'll end up like you!"

"Well, do you oppose me?" He stood up, and Tallia did too, so that he had to look up at her.

"Tallia," said Mendark, "no one cares more for Llian than I do. I ..." he grimaced, "like Karan, too. But there isn't anything we can do for them. Surely you can see that? Does anyone disagree?"

No one spoke. "Well, Shand," said Mendark. "You've more at stake here than I have."

Shand was quite still. A tear leaked out of one eye and ran down his cheek. "I don't see how we can do anything for them!" He turned away abruptly.

"I suppose you're right," Tallia said sadly. "Do what you must do."

"Well, Yggur," said Mendark. "You have your way after all. How do we seal the Nightland?"

"I don't know anymore. I hadn't thought he'd be that strong."

"We don't have power enough to seal it," said Malien. "Unless-" Her eyes slid to the shaft by the fireplace.

"Yes!" roared Mendark. "Brilliant, Malien! So far we've failed for want of power. But if we all work together, and tap a greater source of power-"

"I've already tried it!" cried Yggur, his voice cracking.

"We must," said Mendark softly. "We will go down to the seat of Kandor's power. Down to the rift itself."

"No!" Selial screeched, the only word she had spoken in days.

THE MAP-MASTER.

Tallia sat on the floor with her head hanging. Once again she had failed.

"We hurt Rulke," said Mendark. "And he is unused to the heaviness of our world. Did you see how he labored, climbing the stairs? We've got to act now, before he recovers his strength."

"Ha!" said Tensor in dismal tones. "He has defeated us. Let him have his way."

Malien rose, supporting her injured shoulder with her other hand. "What do you have in mind, Mendark?"

"We three helped to make the Nightland in the first place," he replied. "Me, Tensor and Yggur."

"And when Rulke possessed me you abandoned me!" shouted Yggur. "And Tensor-" His fury overcame him. Yggur stood with head bowed, fists clenched by his sides, his great chest rising and falling. "Tensor betrayed us all! He left a flaw in the Nightland so that he could let Rulke out at a time of his own choosing. Think that I would trust either of you again? Ha!"

Mendark continued calmly. "As I said, we three were there when the Nightland was made. We understand it and we can seal it up again. And when that's done we will tap the power of the rift to make our own gate, and get us straight back to Thurkad."

"The rift failed me two days ago," said Yggur, limping back and forth.

"But you had not the time to study it, to prepare yourself either," Mendark said carefully. "We have that time now."

"It would take years to master," said Yggur.

"Then I'll do it myself," spat Mendark, "with whoever has the courage to aid me." He went out.

"The bloody bastard!" said Yggur to Shand.

"I don't like him either," Shand replied, "but he's right." He drew Yggur to one side. "Come and have a cup of chard with me."

They leaned back against the wall with the chard bowls warming their hands. It was cold here, high in the mountains.

"You cannot begin to know what it was like when the Experiments failed," said Yggur. "Rulke clawed his way into my mind. It was like-I cannot describe it," he cried, "to have him raging in my head."

Shand met his eyes, silently sipping his chard. Yggur needed to talk. Let him say as much as he wanted to, or as little.

"Ever since I became sane again," said Yggur, "the thought of revenge has sustained me. But now I know I'm not his match. I'm afraid to do anything in case Rulke possesses me again." There were tears of helpless rage in his eyes.

"I know that feeling," said Shand, throwing his arm across Yggur's shoulders. Ahh, Karan, how it hurts.

"Mendark pushes me too far," said Yggur, somewhat petulantly.

"He pushes us all," said Shand, "though no harder than himself. He's seen an opportunity that will never come again. If he succeeds, we're free!"

"How can he? How can anyone beat Rulke?"

"Well, let's at least have a go," said Shand.

Tallia peered over the edge of the circular shaft. The glow from below, that had been so bright when Rulke appeared, had died down to nothing. A massive ladder, crusted in stalactites of yellow and brown sulphur, extended down. It was very dark-she could see only half a dozen rungs.

"What's down there?" she asked. No one answered.

Mendark climbed onto a bench and began unscrewing the polished globes from the wall. "Get yourselves a few of these," he said, putting two in his pocket. "Well, who's coming with me?"

"I will," said Tallia, though she was afraid of the underground.

"And I," Shand said after a long pause. His eyes met Malien's, on her stretcher. You're not ready for it, he seemed to be saying.

"The Aachim must be represented. I will send Asper and Xarah with you." Then Malien paused, staring into nowhere. "No, Selial's failure must be balanced. I must come."

"One more," said Mendark, staring at Yggur, who was fidgeting among a stack of food packages in the corner.

The right side of Yggur's face was quite rigid. "I'll be there," he said in a choked voice, "but let it be known that I opposed this folly."

"As you wish," said Mendark. He slung a bag over his shoulder. "Shall we go?"

Tallia followed him almost as reluctantly. She had never liked confined spaces. Sulphur crusts crunched under foot and hand; she felt her hair drawn up to the rungs as she went down.

The floor below the gate chamber, as they now thought of the place that had been Tensor's workroom, was completely empty, though stains on the floor in one place suggested that experiments had been carried out there. The floor below that, the third floor of the tower, was also vacant. The walls and ceiling were hung with crystals yellow, brown and black.

"It's hot!" Asper said, mopping his brow.

"Not as hot as the Dry Sea will be, if we have to walk it," Mendark said tersely.

A puff of acrid air wafted up, sending them into fits of coughing.

"It burns my throat," choked Xarah, a small woman with yellow hair. She and her inseparable twin, Shalah, were the youngest of all the Aachim.

"This place is perilous," said an unusually quiet Asper, wiping streaming yellow eyes with the back of his hand. "The air burns my lungs."

"Then go back, if your kind do not have the courage!" Mendark snapped. "All our options are perilous."

Asper grimaced, as if his honor had been impugned.

They rested at the ground floor, in a room that reeked of brimstone. It was hotter yet.

Below they passed into a vast space cramped with a myriad of pipes that twisted between the tower's complex foundations. Huge cables like coiled springs swept down in outflaring curves from ceiling to floor, crossing one another before plunging into pocked and scaled sockets. There were nine cables, one running up the middle of each of the spiraling rods of stone from which the tower was made. Smaller cables spun away from each of the main ones, holding them in position.

"Ach!" said Asper, ducking his head to walk underneath. "So that's how it works!"

"What?" asked Shand.

"We could not understand how this tower was held up. Being built over the rift, an earth trembler that moved one side more than the other could bring down the whole structure."

"It's stood for two thousand years," said Mendark, impatient to get on.

Asper wasn't listening. "See how the great cable springs hold the tension, while the foundation blocks can move this way and that. What genius!" Then he said, "Malien, Thel, come quickly!"

"What is it?" Shand asked, weaving though the web of smaller cables toward him.

"This block is at the very limit of its travel," said Asper, pointing.

"What does that mean?" asked Xarah.

"It means," said Thel the engineer, "that the next big trembler could unseat the foundations, in which case the tower will surely fall."

"And it may not take a big one," Shand said. "Look at this!"

They all crowded around, save Mendark, who was disappearing down the shaft. Just above its socket one of the huge spring cables, as large around as Shand's chest, was badly corroded beneath the encrusting sulphur. He picked bits of crust off. "The whole structure is under such tension that if this breaks, the other cables must pull the tower down."

"Maybe, maybe not," said Malien, holding her injured shoulder. She was as pale as paper. The one-handed climb down had hurt her. "Let's hope we don't find out."

"Mendark," Tallia called. "Come back!"

Reappearing, he examined the structure with his light-glass. "Hm!" he said, straightening up. "Up top it looks so solid, and all the time this cancer is eating it away from within. Well, no help for it; let's go down."

"It could fall at any moment," said Tallia, biting her lip. She was strong in the face of a known adversary, but this deadly uncertainty undermined her.

"It could. And Rulke could come back at any moment. Or any one of us could fall down the ladder," Mendark said scornfully. "A hundred chance things could kill us every day."

Tallia had to force herself to follow. They had felt earth tremblers here daily, and every day they were stronger. Something was going on deep in the rift. The Great Tower now felt to be resting on eggshells, and she was desperately afraid of being entombed beneath it.

They went down a long way, through a well of layered basalt. Finally they reached the bottom, an excavation into solid rock like an upside-down mushroom with the well as its stalk. The vast room was empty but for several crusted benches carved out of the stone of the floor. A closed-up crack bisected the floor directly underneath the shaft. It was clustered with geyser-like mounds stained red, brown and black.

"The rift!" said Tallia.