We were moving before the first subtle glimmers of dawn had appeared in the sky. I was weary after only a few hours sleep, but Sherlock Holmes seemed to have forgotten what exhaustion was. He was here, there, and everywhere as the last minute preparations went on. He was cheerful, as if the last few days of desperate grasping for answers had never happened. But I remembered his sombre warning of the night before, and it was with some inner trepidation that I bid farewell to my wife and daughter. Mary had spoken cheerfully of Harry. She insisted that she knew almost nothing – though she knew more than I had told her – would have rather asked than answered questions, and, of course, she had no solution. But the few words she spoke on the matter cheered me. She knew that he had a terrible infection of some kind, 'cancerous' she called it. But she did not seem to think his 'cancer' indissociable from him. She did not take for granted that he was doomed. Few and uncertain as her words were, they lent credence to Sherlock's expectations of discovering a solution today. Mr. Pye's letter, little more than a reiteration of what he'd said the day before with better credentials, was disappointing, but not a death knell. The sun had not yet risen over the towers of London when we threw open the doors, and the two helicopters, accompanied by several score wizards on broomsticks, glided out over the dark waters of the Thames.

The whole affair with about the bank was over in short order. Sherlock's and my part in it was but little. We were neither Wizarding fighters, nor official police. I did not even see most of it. Sherlock and I were in the port helicopter, which was co-piloted by George Weasley. His twin was in the other. We rappelled down into the street with the rest. The only people in sight were the two Death Eater guards by the doors, who had fallen to the Order's stunning spells the moment we came into view. In a few moments, through some combination of police explosives and Kingsley Shacklebolt's know-how, the high bronze doors lay twisted upon the ground and we entered.

The goblins, or the few of them that were about when we entered, were surprisingly blasé when Kingsley declared the place claimed by the Order on account of the current administration being an illegal usurpation. Why should they care what the wizards were up to apparently? But they became a little more indignant when they realized that we intended to take something, just one thing, a stolen item, from their vaults. The majority of them put up quite a fuss and cry about it, but it was rather too late to stop us, and a handful of them, less concerned with honour perhaps, or more cognizant of the dangers of Riddle's rule, agreed to cooperate.

I was not among the small team sent down to the caverns to fetch the cup from the Lestrange's vault. I understand that there was a dragon down there; an actual, live, giant, winged reptile, whose exhalations really did combust upon contact with the air. Sherlock tells me it was in a rather in-humane situation, but I should have had a curiosity to see it if I had known. But I was left among the majority of the force.

They returned after a rather more lengthy trip than I had expected, bearing aloft the cup of Helga Hufflepuff. We left the Order and the team to fix the place up, evacuate the goblins (whether they liked it or not) to prevent them from undeservedly bearing the weight of Riddle's wrath, and engineer the 'escape' of some of the captured Death Eaters who had seen what we had taken. And the five of us, Harry, Sherlock, Hermione, Ron, and myself, slipped out of the bank and teleported out of Diagon Alley onto a little hill-side in Northamptonshire just as the sun was rising.

Behind us broad fields stretched away, silver green into the distance, broken by darker patches of woods and hedgerows. The roofs of a tiny hamlet shone out of the fields, not a half a mile to the south-east. From the woods on either hand there rose a loud, merry cacophony of bird sounds. Dew drenched my shoes, and fell in big prism-like droplets from the long leaves of the grass. Before us rose a broad green stretch of rising land. A line of tall trees stood upon the summit, catching the early light. Beyond that was only blue.

Harry let go of Ron's and my hands and unstrapped his firebolt from his back. How far I preferred flying to teleporting! The crushing, the blackness, the roaring in one's ears, the claustrophobic sensation of being dragged through a tunnel, the soreness which often followed – that it was fast, nearly instantaneous, was all that could be said for the one. What could not be said for the other?! There was terror in it, true, and risk; leaving the solid earth so many fathoms behind. But I would choose it without question, make teleporting safe as you may.

We sped upwards, above the ground, but so close to the slope that the long grass still rippled about our ankles, swishing in the wind of our passing. The earth ended above us in a bright green line. Closer and closer came the sky. And then we were up over the top in the air, in the sea of endless blue. Looking back, the earth spread out beneath us, green and bright and more distant by the second. The little hill on which had just been standing was a thumb sized strip between little woodlands. The hamlet flashed its roofs behind us.

I shall never forget that journey, in the sun and the wind, behind Harry Potter on his firebolt, watching the counties drop away beneath us; the green patchwork of fields and hedges of Northamptonshire, the seemingly endless grey mass of Manchester, the high bronze fells and dark valleys of Yorkshire.

The sky over the isle was mostly clear. Some scatted clusters of cumulus clouds appeared in our path from time to time. Harry made no attempt to avoid them. He even rose in elevation once in order to sweep over the top of one towering wall of vapour. It would have made an entire mountain on the ground. So bright, so white, whiter than snow, blinding to look at and unreal to the mind. We see clouds, and our lives are deeply affected by them; we are rescued and we are ruined by that which the clouds bring. But the bright tufts of cotton fluff which race across the summer sky are often little more than images to our minds. We cannot touch them. We cannot approach them. We see them only, and while we may stop and marvel at their beauty and laugh at their form – and in more serious moments worry about what they are or not not bringing – how often are those clouds themselves truly real to us?

It wasn't until Harry purposefully plunged into the side of a ridge that I fully appreciated that this mountain of water was in fact there, not just a beautiful, overly bright image. I touched a cloud. Cool, damp, twilight surrounded us and our faces were pelted by tiny water droplets. The day was becoming quite hot by that time and the sensation was delicious. Casting a glance over my shoulder, I saw the cloud, from this perspective like a very thick fog, rushing away from the path we had blasted through it, and Ron and Sherlock following us through the billowing tunnel. Hermione had gone around. As we came near to the outer edge of the cloud, it suddenly lit up all around us, bright white, gold light, as the vapour particles caught the rays of the sun. It was as if we were swimming in tangible light.

The importance of our mission, the sense that we were embarked upon a great adventure, lent its own spice to the beauty and wonder of the matter. Up there in the sun, it was hard to give much credence to the nightmare visions I had been entertaining recently. With Sherlock's reassurance of his 'last recourse', I could well believe that no great tragedy awaited us in the northern mountains, and I found myself following his admonition – and not despairing at all. Instead I laughed with the Seventh Safeguard, and forgot, if only for an hour, that he was not only the boy that he seemed.

We landed on the banks of a little river which emptied into the Firth of Lorn, and from thence, immediately teleported to Hogwarts School.

I cannot tell you where it lies, save that it is in the north of the Isle. I can say that it is beautiful. And if I were ever to see that valley again, I should know it in an instant. But I can give you no directions thither.

We stood upon a grassy hillside where a number of small, shaggy, red cattle were grazing. Before us, down between the steep green sides of the surrounding highlands, lay a deep wooded valley and a loch. On the banks, I could see the tumbled grey form of a ruined fortress. The grey shapes of real mountains, far above these craggy highlands, rose up in the distance. It was the height of summer, and the highlands and the valley were green and the loch reflected the morning sun so brightly that I could scarcely look at it.

A short walk across the fields brought us to a little country lane, where we assumed our customary disguises. Sherlock was still no more pleased with the gold-tasselled purple hat than he had been the first time Hermione had presented it to him. A little farther down the valley, lay the little village of Hogsmeade.

My first impression was one of extraordinary charm and near idyllic beauty. The shops and houses on either side of the neatly cobbled road were well thatched, beautiful little buildings of antique design but of obviously recent care – care such as given to real houses, real workplaces, and shops, not museum relics. The light of the morning sun filled the street with gold. Green fields stretched right to the borders of the town. Gardens crowded around the buildings and spilled from the window sills. People in bright colours walked the streets. It was as if one had stumbled into another world in this narrow dale, some ancient magical remnant of a world that the rest of the country had left behind, or never quite known at all. That was my first impression.

The second was fear. The faces that passed us by were harried, and carried a hunted expression. A rather large number of the shops and houses, though clearly inhabited and loved till quite recently, had been abandoned, and now stood obviously empty. One of them had been burnt down. The sweetshop into which Ron and Hermione led us was the most marvellous specimen of its kind which I had ever seen. But the middle-aged lady who bustled out of the back had a sad and rather defensive look. A dark hand lay over the town.

By the expedient of causing a disturbance in the front of the shop, we were able to slip down into the basement unnoticed. Harry took some minutes in locating the cleverly concealed trapdoor in the floor, and we passed through it into a flight of stone steps leading down into the earth. These continued for perhaps rather more than the depth of a large house, then ended in an low, narrow tunnel, roughly hewn out of the ground.

Deep underground as we were, and constricted as our movements had to be, it was difficult to gauge just how far we travelled, but I am sure that it was well over a mile before we came to a slope of well laid stone. Up this we climbed, and out through a small opening at the top. This door had clearly been intended solely for the use of very young people. It was a bit of work for me to get through, and I lost a number of my buttons in the process. Once I did, I found myself in a long, high-ceilinged corridor lined with statues (it was through a little door in the back of one of these that we came) and lighted by two high mullioned windows, one at either end.

We were inside the fortress we had seen from the hillside; but it was not the ruin it had appeared. It was Hogwarts School of Witchcraft and Wizardry.

As Sherlock had predicted, the place was very nearly empty, and the few people who were there were easily avoided by the use of Harry's wonderful map. It was an interesting place, Hogwarts. It was odder by far than the old Black house, but there wasn't anything sinister about it. It was odd with an almost charming eccentricity. Also unlike the Black house, it was beautiful, and its grandeur was not mouldering in decay. I might have found it an alarming place if I had been trying to navigate it alone, for not only were the pictures along the walls all animate, like that of Mistress Black, but staircases moved, and doors appeared only sporadically. But I wasn't alone. I was with Harry, Ron, and Hermione, and they knew every corner.

The door to the Room of Requirement was one of the doors which was only visible sometimes. It apparently it would show up only when someone decided that they really wanted it to. One moment there seemed to be only an empty corridor; a large animate tapestry depicting a number of trolls (which were either fighting artistically or dancing violently, one couldn't be sure) on one side, and a bare stone wall on the other. The next moment, a high and rather grand double door had grown out of the bare wall. This sight, which only a week ago would have thrown me into astonishment did not now even cause me to blink.

We passed inside, into a room of vast proportions. In size and shape it was more reminiscent of a cathedral than a storage area, but towering high to the ceiling were stacks and columns, veritable pillars, of miscellaneous objects. Dishes, tools, toys, weapons, clothes, cages, hairbrushes, stuffed animals, closed boxes, papers crumbled into dust, statues, items of furniture, musical instruments, empty bottles, full bottles, gadgets I could not possibly have put a name to or theorized a use for, and things which had long since ceased to have a recognizable form at all were piled in hectic disarray together. There were things whizzing about the ceiling; mechanical, not living, to judge by the noise.

We split up into a line, so as to go over the space more effectively, looking for a ancient diadem on the bewigged head of a crumbling bust, sitting on top of a stained cabinet. Ron found it. Some little time after we had parted among the aisles and piles, he called Harry over to inspect a find and we all came. Harry, Sherlock, and I came empty handed, but Hermione's arms were filled with headdresses of every description – just in case.

After it had made the round of the children, Sherlock took the ancient headpiece in his gloved hands and inspected it very carefully.

"Highly tarnished silver." he said, drawing a finger along the distinctly brown surface. "Rather of the Celtic fashion, but you can see the Roman influence as well. It has definitely been out in the weather for a significant period of time. Besides the effects of water there appears to be a remnant of root wrapped around the silver here and the crumbling substance in this gem clasp is most certainly flecks of broken tree-bark."

"Showing that it was lying around outside somewhere for a long time and hidden in here relatively recently." said Harry.

"Exactly." said Sherlock. He held it up to his own head, but I noticed that he was very careful not to actually touch it to it. "If this was in fact designed specifically to fit Rowena, then it would appear that she had decidedly superior supra-orbital development – either that or she was an exceptionally large woman all around."

"She was known for being the cleverest." said Harry.

"I can well believe it. Is there any significance to sapphires in Hogwarts lore?"

There was no special significance to sapphires, but blue was one of Ravenclaw's colours. Sherlock, Harry, and Hermione were all quite confident that this was the long lost diadem, and Ron and I were quite prepared to take their word for it. And so, bearing the diadem of Ravenclaw, the cup of Hufflepuff, and the locket of Slytherin, the five of us went down to the famed 'chamber of secrets'.

The entrance to the chamber of secrets was located, oddly enough, in a girl's bathroom. The hidden doorway was concealed in one of the fixtures. But the chamber had been built over a millennium ago. So either the chamber was designed to automatically modify itself to adapt to a changing building, or the wizard's of the ninth century had had remarkably modern plumbing technology, or it had been secretly modified many times by descendants of the founder.

The chamber was opened by a password. And it was then that I saw for myself the phenomenon that Sherlock had spoken of. Harry opened the chamber. He stood there and he hissed at it. Under different conditions I would have been inclined to laugh at the bizarre display. But not now. He wasn't making silly animal noises. He was speaking. Speaking a language that he'd never been taught. And the hidden door opened to him; a dank and ill smelling hole angling down into the dark.

Harry shouldn't have been able to speak that language. It suddenly verbalized in my mind thatHarry was not speaking at all. Riddle was. It was that bit of Thomas Riddle, who was standing beside me. And for the first time, though my liking for Harry did not at all decrease, and my pity for him and horror on his account increased, I was almost a little afraid of him.

He turned to us, gave us a reassuring smile which entirely failed to reassure me, and jumped down into the hole. He slid away and disappeared into the blackness. Sherlock followed unhesitatingly. I had never seen a doorway I found less inviting, but there was nothing but to follow them.

Instantly the light of the sun was cut off. I was on a enclosed and seemingly endless slide, going down into the depths below the castle. Just when I was starting to wonder if this was really a slide at all – instead of a bizarre gravitational loop which we were going to be trapped in forever – I slid out of the pipe and onto a wet stone floor. The soft glow of Harry's wand and the sharp beam of Sherlock's flash-light illuminated a rough stone tunnel. Stones had fallen from the roof, and I had a suspicion that it wouldn't take much to make more follow.

We walked silently, flash-lights and wands out. At one point the tunnel had caved in so badly that we had to get down on our hands and knees and crawl through it.

The tunnel ended in a snake adorned door, which opened to Harry's command, and we entered into a chamber, the like of which I had never seen before.

Pillars lined the room. There was light there, a very dim greenish light, but I couldn't tell where it came from. At the far end of the chamber stood a stone colossus, robed and bearded, reaching up to the vaulted ceiling – an image of the long dead Salazar Slytherin. And on the floor at his feet lay a great coiled shape.

We approached it with a certain amount of caution, for even four years dead, with little left but the skeleton and rags of skin, the basilisk was a fearful thing, massive beyond belief. Most of it had rotted away in years since, but a foul odour hung heavily about it.

Harry hastily took the locket from about his neck.

"We'd better not try them all at once. I don't know what they'll do. The diary tried to kill Ginny and me."

"Wasn't the diary intended to be more interactive?" asked Sherlock.

"Yes, but I bet these won't exactly go down without a fight either." said Harry. And he broke off a basilisk fang.

They destroyed them, the three horcruxes, one after another, these outwardly beautiful objects of silver and gold – that held devils inside them. As Harry had expected, they screamed and they taunted and they threatened, they filled the chamber with horrors. But the three children ended them. And we five stood in the dark and filthy chamber in silence, victorious but overwhelmed. There was a very strange and indecipherable look on Sherlock's face. Harry on the other hand, could be read like a book. He was silent in a mixture of disgust, exhaustion, and wonder. After a moment he spoke, and his voice was hushed with excitement.

"That's the diary, the ring, the locket, the cup, and the diadem. Now there's just the snake. And Tom Riddle himself. Mr Holmes! You were right! This will be over before the sun sets!"

And he raced out of the chamber, a basilisk fang in his hand, joyfully heedless of his trainers slipping on the slime.