AN: Just a couple of things: first of all, the letter that Kiara sent to her parents is the last letter that she will write to her parents or Sarabi ever again in this series. Second of all, in two chapters time, there will be a chapter from Sian's point of view which is important, and it will start off somewhere next chapter, but I'll save that information for next week. See you then, and enjoy this chapter.

Chapter 28

The Cave

KIARA

I could smell salt and hear rushing waves; a light, chilly breeze ruffled my hair as I looked out at a moonlit sea and star-strewn sky. I was standing upon a high outcrop of dark rock, water foaming and churning below me. I glanced over my shoulder. A towering cliff stood behind, a sheer drop, black and faceless. A few large chunks of rock, such as the one upon Crighton and I were standing, looked as though they were broken away from the cliff face at some point in the past. It was a bleak, harsh view; the sea and the rock unrelieved by any tree or grass or sand.

"What do you think?" asked Crighton. She might have been asking whether it was a good site for a picnic.

"They brought the kids from the orphanage here?" I asked, for I could not imagine a less cosy spot for a daytrip.

"Not here, precisely," said Crighton. "There is a village of sorts halfway along the cliffs behind us. I believe the orphans were taken there for a little sea air and a view of the waves. No, I think it was only ever Dizra Maliay and her youthful victims who visited this spot. No Muggle could reach this rock unless they were uncommonly good mountaineers, and boats cannot approach the cliffs; the waters around them are too dangerous. I imagine that Maliay climbed down; magic would have served much better than ropes. And she brought two very small children with her, probably for the pleasure of terrorising them. I think the journey alone would have done it, don't you?"

I looked up at the cliff again and felt goosebumps.

"But her final destination - and ours - lies a little further on. Come."

Crighton beckoned me to the very edge of the rock, where a series of jagged nitches that made footholds led down to boulders that lay half-submerged in water and closer to the cliff. It was a treacherous descent and Crighton, hampered slightly by her withered hand, moved slowly. The lower rocks were slippery with sea water. I could feel flecks of cold salt spray hitting my face.

"Lumos," said Crighton, as she reached the boulder closest to the cliff face. A thousand flecks of golden light sparkled upon the dark surface of the water a few feet below where she crouched; the black wall of rock beside us was illuminated too.

"You see?" said Crighton quietly, holding her wand a little higher. I saw a fissure in the cliff into which dark water was swirling.

"You will not object to getting a little wet?"

"No," I said.

"Then take off your Invisibility Cloak - there is no need for it now - and let us take the plunge."

And with the sudden agility of a much younger woman, Crighton slid from the boulder, landed in the sea and began to swim, with a perfect breaststroke, towards the dark slit in the rock face, her lit wand held in her teeth. I pulled off my Cloak, stuffed it into my pocket and followed.

The water was icy; my waterlogged clothes billowed around me and weighed me down. Taking deep breaths that filled my nostrils with the tang of sea salt and seaweed, I struck out for the shimmering, shrinking light now moving deeper into the cliff.

The fissure soon opened into a dark tunnel that I could tell would be filled with water at high tide. The slimy walls were barely three feet apart and glimmered like wet tar in the passing light of Crighton's wand. A little way in, the passageway curved to the left and I saw that it extended far into the cliff. I continued to swim in Crighton's wake, the tips of my benumbed fingers brushing the rough, wet rock.

Then I saw Crighton rising out of the water, her caramel-silver hair and dark robes gleaming. When I reached the spot I found steps that led into a large cave. I clambered up them, water streaming from my soaking clothes, and I emerged, shivering uncontrollably, into the still and freezing air.

Crighton was standing in the middle of the cave, her wand held high as she turned slowly on the spot, examining the walls and ceiling.

"Yes, this is the place," said Crighton.

"How can you tell?" I spoke in a whisper.

"It has known magic," said Crighton simply.

I could not tell whether the shivers I was experiencing were due to my spine-deep coldness or to the same awareness of enchantments. I watched as Crighton continued to revolve on the spot, evidently concentrating on things I could not see.

"This is merely the ante-chamber, the entrance hall," said Crighton after a moment or two. "We need to penetrate the inner place ... now it is Lady Zira's obstacles that stand in our way, rather than those nature made ..."

Crighton approached the wall of the cave and caressed it with her blackened fingertips, murmuring words in a strange tongue that I did not understand. Twice Crighton walked around the cave, touching as much of the rough rock as she could, occasionally pausing, running her fingers backwards and forwards over a particular spot, until finally she stopped, her hand pressed flat against the wall.

"Here," she said. "We go through here. The entrance is concealed."

I did not ask how Crighton knew. I had never seen a witch work things out like this, simply by looking and touching; but I had long since learned that bangs and smoke were more often the marks of ineptitude than experience.

Crighton stepped back from the cave wall and pointed her wand at the rock. For a moment, an arched outline appeared there, blazing white as though there was a powerful light behind the crack.

"You've d-done it!" I said through chattering teeth, but before the words had left my lips the outline hand gone, leaving the rock as bare and solid as ever. Crighton looked round.

"Kiara, I'm so sorry, I forgot," she said; she pointed her wand at me and at once my clothes were as warm and dry as if they had been hanging in front of a blazing fire.

"Thank you," I said gratefully, but Crighton had already turned her attention back to the solid cave wall. She did not try any more magic, but simply stood there staring at it intently, as though something extremely interesting was written on it. I stayed quite still; I did not want to break Crighton's concentration.

Then, after two solid minutes, Crighton said quietly, "Oh, surely not. So crude."

"What is it, Professor?"

"I rather think," said Crighton, putting her uninjured hand inside her robes and drawing out a short silver knife of the kind I used to chop potion ingredients, "that we are required to make payment to pass."

"Payment?" I said. "You've got to give the door something?"

"Yes," said Crighton. "Blood, if I am not mistaken."

"Blood?"

"I said it was crude," said Crighton, who sounded disdainful, even disappointed, as though Zira had fallen short of the standards Crighton expected. The idea, as I am sure you will have gathered, is that your enemy must weaken him or herself to enter. Once again, Lady Zira fails to grasp that there are much more terrible things than physical injury."

"Yeah, but still, if you can avoid it ..." I said, having experienced enough pain to be keen for no more.

"Sometimes, however, it is unavoidable," said Crighton, shaking back the sleeve of her robes and exposing the forearm of her injured hand.

"Professor!" I protested, hurrying forwards as Crighton raised her knife. "I'll do it, I'm - "

I did not know what I was going to say - younger, fitter? But Crighton merely smiled. There was a flash of silver, and a spurt of scarlet; the rock face was peppered with dark, glistening drops.

"You are very kind, Kiara," said Crighton, now passing the tip of her wand over the deep cut she had made in her own arm, so that it healed instantly, just as Triphorm had healed Malty's wounds. "But your blood is worth more than mine. Ah, that seems to have done the trick, doesn't it?"

The blazing silver outline of an arch had appeared in the wall once more, and this time it did not fade away: the blood-spattered rock within it simply vanished, leaving an opening into what seemed total red darkness.

"After me, I think," said Crighton, and she walked through the archway. I followed her, lighting my own wand hastily as I went.

An eerie sight met our eyes: we were standing on the edge of a great red lake - and I do mean that literally, for the water was red, and no, it was not blood - so vast that I could not make out the distant banks, because the walls were also the same dark red as the lake, in a cavern so high that the ceiling, too, was out of sight. A misty greenish light shone far away in what looked like the middle of the lake; it was reflected in the completely still water below. The greenish glow and the light from the two wands were the only things that broke the otherwise velvety redness, though their rays did not penetrate as far as I would have expected. The red darkness was of a very dense type indeed.

"Let us walk," said Crighton quietly. "Be very careful not to step into the water. Stay close to me."

She set off around the edge of the lake and I followed close behind her. Our footsteps made echoing, slapping sounds on the narrow rim of rock that surrounded the water. On and on we walked, but the view did not vary: on one side of us, the rough cavern wall; on the other, the boundless expanse of smooth, glassy redness, in the very middle of which as the mysterious greenish glow. I remember finding the place and the silence oppressive, unnerving (to this day, I still get chills about that place).

"Professor?" I said finally. "Do you think the Horcrux is here?"

"Oh yes," said Crighton. "Yes, I'm sure it is. The question is, how do we get to it?"

"We couldn't ... we couldn't just try a Summoning Charm?" I said, sure that it was a stupid suggestion, but much keener than I was prepared to admit to getting out of that place as soon as possible.

"Certainly we could," said Crighton, stopping so violently that I almost walked into her. "Why don't you do it?"

"Me? Oh ... OK ..."

I had not expected this, but I cleared my throat and said loudly, and aloft, "Accio Horcrux!"

With a noise like an explosion, something very large and pale erupted out of the dark water some twenty feet away, before I could see what it was, it had vanished again with a crashing splash that made great, deep ripples on the mirrored surface. I leapt backwards in shock and hit the wall; my heart was still thundering as I turned to Crighton.

"What was that?"

"Something, I think, that is ready to respond should we attempt to seize the Horcrux."

I looked back at the water. The surface of the lake was once more shining red glass; the ripples had vanished unnaturally fast; my heart, however, was still pounding.

"Did you think that would happen, ma'am?"

"I thought something would happen if we made an obvious attempt to get our hands on the Horcrux. That was a very good idea, Kiara; much the simplest way of finding out what we are facing."

"But we don't know what that thing was," I said, looking at the sinisterly smooth water.

"What the things are, you mean," said Crighton. "I doubt very much that there is only one of them. Shall we walk on?"

"Professor?"

"Yes, Kiara?"

"Do you think we're going to have to go into the lake?"

"Into it? Only if we are very unfortunate."

"You don't think the Horcrux is at the bottom?"

"Oh no ... I think the Horcrux is in the middle."

And Crighton pointed towards the misty green light in the centre of the lake.

"So we're going to have to cross the lake to get to it?"

"Yes, I think so."

I did not say anything. My thoughts were all of water monsters, of giant serpents, of demons, kelpies and sprites ...

"Aha," said Crighton and she stopped again; that time, I really did walk into her; for a moment I toppled on the edge of the dark water and Crighton's uninjured hand closed tightly around my upper arm, pulling me back. "So sorry, Kiara, I should have given warning. Stand back against the wall, please, I think I have found the place."

I had no idea what Crighton meant; this patch of dark bank was exactly like every other bit as far as I could tell, but Crighton seemed to have detected something special about it. This time she was running her hand not over the rocky wall, but through the thin air, as though expecting to find and grip something invisible.

"Aha," said Crighton happily, seconds later. Her hand had closed in mid-air upon something I could not see. Crighton moved closer to the water; I watched nervously as the tips of Crighton's buckled shoes found the utmost edge of the rock rim. Keeping her hand clenched in mid-air, Crighton raised her wand with the other and tapped her fist with the point.

Immediately a thick coppery green chain appeared out of thin air, extending from the depths of the water into Crighton's clenched hand. Crighton tapped the chair, which began to slide through her fist like a snake, coiling itself on the ground with a clinking sound that echoed noisily off the rocky walls, pulling something from the depths of the black water. I gasped as the ghostly prow of a tiny boat broke through the surface, glowing as green as the chain, and floated, with barely a ripple, towards the place on the bank where Crighton and I stood.

"How did you know that was there?" I asked in astonishment.

"Magic always leaves traces," said Crighton, as the boat hit the bank with a gentle bump, "sometimes very distinctive traces. I taught Dizra Maliay. I know her style."

"Is ... is this boat safe?"

"Oh yes, I think so. Zira needed to create a means to cross the lake within it, in case she ever wanted to visit or remove her Horcrux."

"So the things in the water won't do anything to us if we cross in Zira's boat?"

"I think we must resign ourselves to the fact that they will, at some point, realise we are not Lady Zira. Thus far, however, we have done well. They have allowed us to raise the boat."

"But why have they let us?" I asked, for I could not shake off the vision of tentacles rising out of the dark water the moment we were out of sight of the bank.

"Zira would have been reasonably confident that none but a very great wizard would have been able to find the boat," said Crighton. "I think she would have been prepared to risk what was, to her mind, the most unlikely possibility that somebody else would find it, knowing that she had set obstacles ahead that only she would be able to penetrate. We shall see whether she is right."

I looked down into the boat. It really was very small.

"It doesn't look like it was built for two people. Will it hold both of us? Will we be too heavy?"

Crighton chuckled.

"Zira will not have cared about the weight, but about the amount of magical power that crossed her lake. I rather think an enchantment will have been placed upon this boat so that only one wizard at a time will be able to sail in it."

"But then - ?"

"I do not think you will count, Kiara: you are under age and unqualified. Zira would never have expected a sixteen-year-old to reach this place: I think it unlikely that your powers will register compared to mine."

These words did nothing to raise my morale; perhaps Crighton knew it, for she added, "Zira's mistake, Kiara, Zira's mistake ... age is foolish and forgetful when it underestimates youth ... now, you first this time, and be careful not to touch the water."

Crighton stood aside and I climbed carefully into the boat. Crighton stepped in, too, coiling the chain on to the floor. We were crammed in together; I could not comfortably sit, but crouched, my knees jutting over the edge of the boat, which began to move at once. There was no sound other than the silken rustle of the boat's prow cleaving the water; it moved without our help, as though an invisible rope were pulling it onwards towards the light in the centre. Soon we could no longer see the walls of the cavern; we might have been at sea except that there were no waves.

I looked down and saw the reflected silver of my wandlight sparkling and glittering on the red water as we passed. The boat was carving deep ripples upon the glassy surface, grooves in the dark red mirror ...

And then I saw it, marble-white, floating inches below the surface.

"Professor!" I said, and my startled voice echoed loudly over the silent water.

"Kiara?"

"I think I saw a hand in the water - a human hand!"

"Yes, I am sure you do," said Crighton calmly.

I stared down into the water, looking for the vanished hand, and a sick feeling rose in my throat.

"So that thing that jumped out of the water - ?"

But I had my answer before Crighton could reply; the wand-light had slid over a fresh patch of water and showed me, this time, a dead woman lying face up inches beneath the surface: her open eyes misted as though with cobwebs, her hair and her robes swirling around her like smoke, and the red water made it look like she was bleeding fresh blood.

"There are bodies in here!" I said, and my voice sounded much higher than usual and most unlike my own.

"Yes," said Crighton placidly, "but we do not need to worry about them at the moment."

"At the moment?" I repeated, tearing my gaze from the water to look at Crighton.

"Not while they are merely drifting peacefully below us," said Crighton. "There is nothing to be feared from a body, Kiara, any more than there is to be feared from the darkness. Lady Zira, who of course secretly fears both, disagrees. But once again she reveals her own lack of wisdom. It is the unknown we fear when we look upon death and darkness, nothing more."

I said nothing; I did not want to argue, but I found the idea that there were bodies floating around and beneath us horrible, and what was more, I did not believe that they were not dangerous.

"But one of them jumped," I said, trying to make my voice as level and as calm as Crighton's. "When I tried to summon the Horcrux, a body leapt out of the lake."

"Yes," said Crighton. "I am sure that once we take the Horcrux, we shall find them less peaceable. However, like many creatures that dwell in cold and darkness, they fear light and warmth, which we shall therefore call to our aid should the need arise. Fire, Kiara," Crighton added with a smile, in response to my bewildered expression.

"Oh ... right ..." I said quickly. I turned my head to look at the greenish glow towards which the boat was inexorably sailing. I could not pretend, at that moment, that I was not scared. The great red lake, teeming with the dead ... it seemed hours and hours ago that I had met Professor Crystals, that I had given Chris and Chrissie the Felix Felicis ... I suddenly wished that I had said a better goodbye to them ... and I hadn't said a proper goodbye to Sian, either ...

"Nearly there," said Crighton cheerfully.

Sure enough, the greenish light seemed to be growing larger at last, and within minutes, the boat had come to a halt, bumping gently into something that I could not see at first, but when I raised my illuminated wand I saw that we ha reached a small island of smooth rock in the centre of the lake.

"Careful not to touch the water," said Crighton again as I climbed out of the boat.

The island was no larger than Crighton's office: an expanse of flat dark stone on which stood nothing but the source of that dark greenish light, which looked much brighter when viewed close to. I squinted at it; at first I thought it was a lamp of some kind, but then I saw that the light was coming from a stone basin rather like the Pensieve, which was set on top of a pedestal.

Crighton approached the basin and I followed. Side by side we looked down into it. The basin was full of an emerald liquid emitting the phosphorescent glow.

"What is it?" I asked quietly.

"I am not sure," said Crighton. "Something more worrisome than blood and bodies, however."

Crighton pushed back the sleeve of her robe over her blackened hand, and stretched out the tips of her burned fingers towards the surface of the potion.

"Ma'am, no, don't touch - !"

"I cannot touch," said Crighton, smiling gently. "See? I cannot approach any nearer than this. You try."

Staring, I put my hand into the basin and attempted to touch the potion. I met an invisible barrier that prevented me coming within an inch of it. No matter how hard I pushed, my fingers encountered nothing but what seemed to be solid and inflexible air.

"Out of the way, please, Kiara," said Crighton.

She raised her wand and made complicated movements over the surface of the potion, murmuring soundlessly. Nothing happened, except perhaps that the potion glowed a little brighter. I remained silent while Crighton worked, but after a while Crighton withdrew her wand and I felt it was safe to talk again.

"You think the Horcrux is in there, ma'am?"

"Oh, yes." Crighton peered more closely into the basin. I saw her face reflected, upside-down, in the smooth surface of the green potion. "But how to reach it? This potion cannot be penetrated by hand, vanished, parted, scooped up or siphoned away, nor can it be Transfigured, Charmed or otherwise made to change its nature."

Almost absent-mindedly, Crighton raised her wand again, twirled it once in mid-air and then caught the crystal goblet that she had conjured out of nowhere.

"I can only conclude that this potion is supposed to be drunk.

"What?" I said. "No!"

"Yes, I think so: only by drinking it can I empty the basin and see what lies in its depths."

"But what if - what if it kills you?"

"Oh, I doubt that it would work like that," said Crighton easily. "Lady Zira would not want to kill the person who reached this island."

I couldn't believe it. Was this more of Crighton's determination to see the good in everyone?

"Ma'am," I said, trying to keep my voice reasonable, "ma'am, this is Zira we're - "

"I'm sorry, Kiara; I should have said, she would not want immediately to kill the person who reached this island," Crighton corrected herself. "She would want to keep them alive long enough to find out how they managed to penetrate so far through her defences and, most importantly of all, why they were so intent upon emptying the basin. Do not forget that Lady Zira believes that she alone knows about her Horcruxes."

I made to speak again, but this time Crighton raised her hand for silence, frowning slightly at the emerald liquid, evidently thinking hard.

"Undoubtedly," she said finally, "this potion must act in a way that will prevent me taking the Horcrux. It might paralyse me, cause me to forget what I am here for, create so much pain I am distracted, or render me incapable in some other way. This being the case, Kiara, it will be your job to make sure I keep drinking, even if you have to tip the potion into my protesting mouth. You understand?"

Our eyes met over the basin; each pale face lit with that strange, green light. I did not speak. Was this why I had been invited along - so that I could force-feed Crighton a potion that might cause her unendurable pain?

"You remember," said Crighton, "the condition on which I brought you with me?"

I hesitated, looking into the green eyes that had turned greener in the reflected light of the basin.

"But what if - ?"

"You swore, did you not, to follow any command I gave you?"

"Yes, but - "

"I warned you, did I not, that there might be danger?"

"Yes," I said, "but - "

"Well, then," said Crighton, shaking back her sleeves once more and raising the empty goblet, "you have my orders."

"Why can't I drink the potion instead?" I asked desperately.

"Because I am much older, much cleverer, and much less valuable," said Crighton. "Once and for all, Kiara, do I have your word that you will do all in your power to make me keep drinking?"

"Couldn't - ?"

"Do I have it?"

"But - "

"Your word, Kiara."

"I - all right, but - "

Before I could make any further protest, Crighton lowered the crystal goblet into the potion. For a split second I hoped she would not be able to touch the potion with the goblet, but the crystal sank into the surface as nothing else had; when the glass was full to the brim, Crighton lifted it to her mouth.

"Your good health, Kiara."

And she drained the goblet. I watched, terrified, my hands gripping the rim of the basin so hard that my fingertips were numb.

"Professor?" I said anxiously, as Crighton lowered the empty glass. "How do you feel?"

Crighton shook her head, her eyes closed. I wondered whether she was in pain. Crighton plunged the glass blindly back into the basin, refilled it, and drank once more.

In silence, Crighton drank three gobletfuls of the potion. Then, halfway through the fourth goblet, she staggered and fell forwards against the basin. Her eyes were still closed, her breathing heavy.

"Professor Crighton?" I said, my voice strained. "Can you hear me?"

Crighton did not answer. Her face was twitching as though she were deeply asleep, but dreaming a horrible dream. Her grip on the goblet was slacking; the potion was about to spill from it. I reached forwards and grasped the crystal cup, holding it steady.

"Professor, can you hear me?" I repeated loudly, my voice echoing around the cavern.

Crighton panted and then spoke in a voice I did not recognise, for I had never heard Crighton frightened like she was.

"I don't want ... don't make me ..."

I stared into the whitened face I knew so well, at the crooked nose and caramel-silver hair, and I did not know how to comfort her. No wonder Crighton had not let Sian come with us; after all, what child would want to see their parent in that state?

" ... don't like ... want to stop ..." moaned Crighton.

"You ... you can't stop, Professor," I said. "You've got to keep drinking, remember? You told me you had to keep drinking. Here ..."

I didn't want to do it, but what choice did I have; I had promised Crighton that I would obey any order she gave me. So, hating myself, repulsed by what I was doing, I forced the goblet back towards Crighton's mouth and tipped it, so that Crighton drank the remainder of the potion inside.

"No," she groaned, as I lowered the goblet back into the basin and refilled it for her. "I don't want to ... I don't want to ... let me go ..."

"It's all right, Professor," I said, my hand shaking. "It's all right, I'm here - "

"Make it stop, make it stop," moaned Crighton.

"Yes ... yes, this'll make it stop," I lied. I tipped the contents of the goblet into Crighton's open mouth.

Crighton screamed; the noise echoed all around the vast chamber, across the dead red water.

"No, no, no ... no ... I can't, don't make me, I don't want to ..."

"It's all right, Professor, it's all right!" I said loudly, my hands shaking so badly I could hardly scoop up the sixth gobletful of potion; the basin was now half-empty. "Nothing's happening to you, you're safe, it isn't real, I swear it isn't real - take this, now, take this ..."

And obediently, Crighton drank, as though it was an antidote I offered her; but upon draining the goblet, she sank to her knees, shaking uncontrollably.

"It's all my fault, all my fault," she sobbed, "please make it stop, I know I did wrong, oh, please make it stop and I'll never, never again ..."

"This will make it stop, Professor," I said, my voice cracking as I tipped the seventh glass of potion into Crighton's mouth.

Crighton began to cower as though invisible torturers surrounded her; her flailing hand almost knocked the refilled goblet from my trembling hands as she moaned, "Don't hurt them, don't hurt them, please, please, it's all my fault, hurt me instead ..."

"Here, drink this, you'll be all right," I said desperately, and once again Crighton obeyed me, opening her mouth even as she kept her eyes tight shut and shook from head to foot.

And now she fell forwards, screaming again, hammering her fists upon the ground, while I filled the ninth goblet.

"Please, please, please, no ... not that, not that, I'll do anything ..."

"Just drink, Professor, just drink ..."

Crighton drank like a child crying of thirst, but when she had finished, she yelled again as though her insides were on fire.

"No more, please, no more ..."

I scooped up a tenth gobletful of potion and felt the crystal scrape the bottom of the basin.

"We're nearly there, Professor, drink this, drink it ..."

I supported Crighton's shoulders and again, Crighton drained the glass; I was on my feet once more, refilling the goblet as Crighton began to scream in more anguish than ever, "I want to die! I want to die! Make it stop, make it stop, I want to die!"

"Drink this, Professor, drink this ..."

Crighton drank, and no sooner had she finished than she yelled, "KILL ME!"

"This - this one will!" I gasped. "Just drink this ... it'll be over ... all over!"

Crighton gulped at the goblet, drained every last drop, and then, with a great, rattling gasp, rolled over on to her face.

"No!" I shouted, for I had stood to refill the goblet again; instead I dropped the cup into the basin, flung myself down beside Crighton and heaved her over on to her back; Crighton's mouth was agape and her eyes were closed. "No," I said, shaking Crighton, "no, you're not dead, you said it wasn't poison, wake up, wake up - Rennervate!" I cried, pointing my wand at Crighton's chest; there was a flash of red light but nothing happened. "Rennervate - ma'am - please - "

Crighton's eyes flickered; my hear leapt.

"Ma'am, are you - ?"

"Water," croaked Crighton.

"Water," I panted, "yes - "

I leapt to my feet and seized the goblet I had dropped in the basin; I barely registered the golden locket lying curled beneath it. "Aguamenti!" I shouted, jabbing the goblet with my wand.

The goblet filled with clear water; I dropped to my knees beside Crighton, raised her head and brought the glass to her lips - but it was empty. Crighton groaned and began to pant.

"But I had some - wait - Aguamenti!" I said again, pointing my wand at the goblet. Once more, for a second, clear water gleamed within it, but as I approached Crighton's mouth, the water vanished again.

"Ma'am, I'm trying, I'm trying!" I said desperately, but I did not think that Crighton could hear me; she had rolled on to her side and was drawing great, rattling breaths that sounded agonising. "Aguamenti - Aguamenti - AGUAMENTI!"

The goblet filled and emptied once more. And now Crighton's breath was fading. My brain whirling in panic, I knew, instinctively, the only way left to get water, because Zira had planned it so ...

I flung myself over to the edge of the rock and plunged the goblet into the lake, brining it up full to the brim of icy water that did not vanish.

"Ma'am - here!" I yelled, and lunging forwards I tipped the water clumsily over Crighton's face.

It was the best I could do, for the icy feeling on my arm not holding the cup was not the lingering chill of the water. A slimy white hand had gripped my wrist, and the creature to whom it belonged was pulling me, slowly, backwards across the rock. The surface of the lake was no longer mirror-smooth; it was churning, and everywhere I looked, white heads and hands were emerging from the dark water, men and women and children with sunken, sightless eyes were moving towards the rock; an army of the dead rising from the red water.

"Petrificus Totalus!" I yelled, struggling to cling on to the smooth, soaked surface of the island as I pointed my wand at the Inferius that had my arm: it released me, falling backwards into the water with a splash. I scrambled to my feet; but many more Inferi were already climbing on to the rock, their bony hands clawing at its slippery surface, their blank, frosted eyes upon me, trailing waterlogged rags, sunken faces leering.

"Petrificus Totalus!" I bellowed again, backing away as I swiped my wand through the air; six or seven of them crumpled, but more were coming towards me. "Impedimenta! Incarcerous!"

A few of them stumbled, one or two of them bound in ropes, but those climbing on to the rock behind them merely stepped over or on the fallen bodies. Still slashing at the air with my wand, I yelled, "Sectumsempra! SECTUMSEMPRA!"

But though gashes appeared on their sodden rags and their icy skin, they had no blood to spill: they walked on, unfeeling, their shrunken hands outstretched towards me, and as I backed away still further I felt arms enclose me from behind, thin, fleshless, arms cold as death, and my feet left the ground as they lifted me and began to carry me, slowly and surely, back to the water, and I knew there would be no release, that I would be drowned, and become one more dead guardian of a fragment of Zira's shattered soul ...

But then, through the darkness, fire erupted: crimson and gold, a ring of fire that surrounded the rock so that the Inferi holding me so tightly stumbled and faltered; they did not dare pass through the flames to get to the water. They dropped me; I hit the ground, slipped on the rock and fell, grazing my arms, but I scrambld back up, raising my wand and staring around.

Crighton was on her feet again, pale as any of the surrounding Inferi, but taller than any, too, the fire dancing in her eyes; her wand was raised like a torch and from its tip emanated the flames, like a vast lasso, encircling us all with warmth.

The Inferi bumped into each other, attempting, blindly, to escape the fire in which they were enclosed ...

Crighton scooped up the locket from the bottom of the stone basin and stowed it inside her robes. Wordlessly, she gestured to me to come to her side. Distracted by the flames, the Inferi seemed unaware that their quarry was leaving as Crighton led me back to the boat, the ring of fire moving with us, around us, the bewildered Inferi accompanying us to the water's edge, where they slipped gratefully back into the dark red waters.

I was shaking all over, but at that moment I was more concerned about Crighton, for I thought for a moment that she might not be able to climb back into the boat; she staggered a little as she attempted it; all her efforts seemed to be going into maintaining the ring of protective flame around us. I seized her and helped her back to her seat. Once we were both safely jammed inside again, the boat began to move back across the red water, away from the rock, still encircled by that ring of fire, and it seemed that the Inferi swarming below us did not dare resurface.

"Ma'am," I panted, "ma'am, I forgot - about fire - they were coming at me and I panicked - "

"Quite understandable," murmured Crighton. I was alarmed to hear how faint her voice was.

We reached the bank with a little bump and I leapt out, then I turned quickly to help Crighton. The moment that Crighton reached the bank she let her wand fall; the ring of fire vanished, but the Inferi did not emerge again from the water. The little boat sank into the water once more; clanking and tinkling, its chain slithered back into the lake, too. Crighton gave a great sigh and leaned against the cavern wall.

"I am weak ..." she said.

"Don't worry, ma'am," I said at once, anxious about Crighton's extreme pallor and her air of exhaustion. "Don't worry, I'll get us back ... lean on me, ma'am ..."

And pulling Crighton's uninjured arm around my shoulders, I guided my headmistress back around the lake, bearing most of her weight.

"The protection was ... after all ... well designed," said Crighton faintly. "One alone could not have done it ... you did well, very well, Kiara ..."

"Don't talk now," I said, fearing how slurred Crighton's voice had become, how much her feet dragged, "save your energy, ma'am ... we'll soon be out of here ..."

"The archway will have sealed again ... my knife ..."

"There's no need, I got cut on the rock," I said firmly, "just tell me where ..."

"Here ..."

I wiped my grazed forearm upon the stone: having received its tribute of blood the archway reopened instantly. We crossed the outer cave and I helped Crighton back into the icy sea water that filled he crevice in the cliff.

"It's going to be all right, ma'am," I said over and over again, more worried by Crighton's silence than I had been by her weakened voice. "We're nearly there ... I can Apparate us both back ... don't worry ..."

"I am not worried, Kiara," said Crighton, her voice a little stronger despite the freezing water. "I am with you."