Alodar nodded and motioned to the archway, suddenly pleased with himself for what he had said and the reaction it had caused. Without another word, they left the chamber and returned to the flanking tower. As they began to climb down to the bottommost level, the ground shook again like a blanket snapped taut on a newly made bed, and the rumble echoed about them so that neither could speak. As the reverberations died, a man-at- arms poked his head through the opening to the level above.
'Lady Aeriel, come quickly to the queen's bidding,' he shouted down. 'A strange occurrence in the central chamber.'
Alodar and Aeriel quickly reversed direction, following the man back to the queen. Everyone of their small band was there, filling the room, and all heads looked anxiously upwards towards the huge vault of the ceiling. Vendora was where Alodar had seen her last, but now she stood propped against Feston, leaning heavily on the arm he wrapped around her.
A sudden streak of motion caught Alodar's eye. He turned his head upward to see several large drops of opaque liquid ooze out between two of the massive stones. They fell and spattered against the rusty slab at the chamber's center and added to the messy orange slurry of their predecessors.
He frowned in concentration. Nothing from thaumaturgy certainly, he thought. But what had Periac told him of the other arts? What would seep through what no mason could chisel in a week?
'Solvent!' he yelled as the answer struck him. 'And it looks high grade. Everyone out! The ceiling is going to collapse. That is how the towers were toppled. They are dissolving the mortar between the stones.'
No one moved. All were transfixed by the slowly increasing tempo of the drip and the widening pool on the chamber floor. Before Alodar could say more, the giant keystone in the center of the vault began to slide slowly down and away from the rock which surrounded it. It gathered speed; with a cascade of liquid on every side, it fell away entirely, into their midst. With a resounding crash, it hit the slab and sprayed liquid and splinters of rock in all directions. The crowd screamed and sprang alive, bolting for the passageways, shouldering one another aside in their haste.
Alodar and Aeriel moved to one side to let them pass, their eyes on the queen across the chamber. Feston, with his grip still on Vendora's arm, spun her towards the nearest exit and pushed her ahead. Periac recovered his balance from a brushing blow and plunged after the queen. Festil immediately followed, almost catching the thaumaturge's cape with his long running stride.
Alodar looked again at the ceiling. Through the new opening, Bandor's men were lowering a rope ladder and several were making ready to descend. He glanced over his shoulder into the passageway from which he had just entered and then hesitated no longer. Grabbing Aeriel's hand, he raced across the room, avoiding the many small pools of solvent which were now working on the seams in the floor. As he passed the slab, his eyes was caught by its now shining brilliance. The bath had cleaned away the rust and a good portion of the iron as well.
He stopped suddenly and looked again. The shine was not from the iron alone.
'Look, Aeriel,' he exclaimed. 'In the center of the iron, a disk of copper! It is not a solid iron slab, after all. Beneath the rust is this circle of copper in a yoke of iron. A circle at each level. The copper here, the column below, and a well at the bottom of it all.'
Three circles of the same diameter! One above the other. In a flash the castle's secret came to him. He looked again at the rope ladder. Two men were already gently swinging on it. He grabbed Aeriel again and ran off after the others. He had the answer. If there was only enough time to use it.
CHAPTER FOUR
The Hero's Reward
THE passageway blurred by and Alodar glanced back over his shoulder. Bandor's men were already in the tunnel after him. He increased his speed; the drawn swords shining in the torchlight gave his legs urgency even beyond what he had felt two days before when the outer walls had fallen. He squeezed Aeriel's hand tighter, and they rapidly closed on Vendora and the others up ahead.
They caught the queen just as they entered the small room under the corner tower. The panicked flight momentarily stopped in a mass confusion of waving arms and shouted directions.
'Up, up to the surface. It is our only chance,' yelled Festil as he tumbled Periac down from the stairs and started to climb.
'No, no father,' Feston boomed louder still. 'See the stonework. We must go down.' As he spoke, he yanked Vendora out of the way of dripping liquid that began to ooze from the ceiling and pushed her through the opening in the floor.
Everyone clambered after. As Alodar brought up at the rear, he saw the small group disappear into the passageway that led back under the keep.
'We will make our stand around the pillar,' Festil shouted back to the three soldiers who now ran with him. They drew their swords as they raced, and Aeriel instinctively started to follow.
Alodar grabbed her by the arm and held her back. 'Our only chance lies below,' he said. 'Let us hope that Feston and the others can hold them off until the spell is finished.'
He plunged down to the bottom level, pulling Aeriel with him. The staircase seemed to spiral for an eternity and his heartbeat almost drowned out the clank of mail and shouts of the chase that now filtered down after them.
Finally at the bottom, he raced for the central chamber, scarcely noticing the diminishing noise as the hunters chose to pursue the quarry one level above. In a moment they reached their destination and saw the serene pool at the center. Alodar looked rapidly about. They were alone.
'Quickly, Aeriel,' he said, 'your ring. No, no the unadorned one. Gold is not the best choice and we must at least make the shape as similar as we can.'
Aeriel slipped one of the rings from her finger and, with a puzzled expression, handed it to Alodar. Without pausing for explanation, he fumbled in a pouch at his waist and withdrew a small collection of coins.
'At least the copper will be right,' he said as he quickly tried matching the coins one by one to the shape of the ring. 'Ah, this one jams in properly. Now fill the cup with the water from the well.'
Aeriel took the cup he whisked from his cape and dipped it in the pool. 'What spell do you cast here, Alodar? I see that the coin in the ring is like the copper disk in the iron collar we saw bared above. But their intent I still cannot fathom.'
'The cool water of the well will shrink the metals slightly,' he replied, 'and because they are different, the copper disk will slip free.'
'But what can we use for the energy source? There is naught here but stone and water,' Aeriel said, waving her arms about the empty chamber.
'You listened to master Periac well,' Alodar said, 'but no source is needed for this spell. Rather, we need a sink to absorb the heat we extract from the hunks of metal two levels above. And the water in the well will serve that purpose for us. Now stand close to me, for in truth I know not all that will happen.'
Alodar glanced quickly into the four passageways, but no figures fleeing or pursuing showed in them, and he began the binding. When be was done, he thrust the ring holding the coin into the numbing cold of the water and held it motionless. Simultaneously the stillness of the pool was broken by the eruption of tiny bubbles all across its surface.
Alodar held the ring firmly, though his fingers began to ache with the cold. The simmer of the pool changed into a boil, growing more vigorous by the second, and the first wisps of steam crept upward into the already dripping air.
Alodar looked anxiously back and forth between the now scalding well and the placid ring. Was it cold enough? Was there enough water in the well?
The feeling left his hand and the opaqueness of the steam engulfed them; so the passageways were blotted from view and the oil lights in the wall became dim and diffuse.
Finally as the fog closed in, the copper coin dropped clear of the ring and gently fell to the bottom of the cup.
'Look to the ceiling,' Alodar shouted as he tore his eyes from what he held. Brushing aside the vapor, they
