Brompton Road tube station was like something from a different era. The faded cream and burgundy tiles at platform level would lead up to the terracotta-coloured surface level building in classic Leslie Green style. The basic colour scheme, which was designed to help illiterate Londoners navigate their way around the underground network, was in stark contrast to the hugely modern cathedral-like stations at Canary Wharf and the like.

But Hermione felt it was far more suited to the magical world, and the clandestine operation that it was a front for.

Regulus Black led Hermione from the platform, past the converted station office - which was now a Floo Network Listening post - and up the escalator towards the old ticket hall. This too had been altered. On one side were a number of cages, containing disgruntled-looking owls, ones who had been intercepted mid-flight and were in the process of having their cargo checked over. On the opposite wall were a set of hourglasses not too dissimilar to the one which recorded the house points at Hogwarts.

"What are they for?" Hermione queried as they passed.

"Apparition Trackers," Regulus explained. "Every magical person has their own magical signature, sort of like a fingerprint, if you like. In the same way that a small trace of residual magic from a witch or wizard can be detected following spell casting, Apparition leaves a similar imprint behind. St Mungo's makes note of this personal signature as part of their birthing records, but all magical families who own House-Elves are required to register them, too.

"The Auror Office and DMLE have the capacity to track Apparition as part of their duties in law enforcement. Luckily for us, Amelia Bones is a prominent member of Brompton Road and helped us set up an identical tracking system here. So all we have to do is target people we are monitoring, and their House-Elves if necessary, to see where they are going."

"And the official bodies do the same?" Hermione asked. "Is … is that why Harry hasn't sent Dobby to me? They know he's volunteered himself into Harry's service, don't they?"

Regulus nodded darkly. "Albus had to register Dobby as Harry Potter's elf … to stop the authorities pursuing him."

"Excuse me!" Hermione cried angrily, rounding on Regulus. "What do you mean pursuing him?"

"House-elves are powerful creatures, Miss Granger," Regulus replied. "Some wizards fear them, you know, and the idea of elves running around freely is abhorrent to such people. In fact, there are even those who advocate the complete corralling of all non-human magical beings. I believe you must have come across Dolores Umbridge, from her time at Hogwarts? She has been championing such changes to the law for years."

Hermione felt a wave of sickness rise into her throat at the mere mention of that toad. Her unspeakable activities only made that bile sting a bit more sharply on Hermione's tonsils.

"But Dobby told me that elves need to be around humans, to renew themselves to survive," Hermione frowned. "If bitches like Umbridge wanted elves to die, why not just let them roam free?"

Regulus quirked a smirk at Hermione. "You didn't strike me as the type to be quite so pig-headed and arrogant, Miss Granger."

"Excuse me?" Hermione huffed back.

"You are excused," Regulus snickered. "Because you are as ignorant as most humans."

"Can you please explain these insults … before I hex you for them!"

Regulus laughed deeply. "Your suggestion, Miss Granger, is that elves - and any other magical creature by proxy - are dependent on us humans to survive. I assure you that you are quite, quite wrong about that."

"But Dobby said he chose to be around Harry, to renew himself!" Hermione argued hotly, greatly offended not only by Regulus' insult but by the possibility that he might be right.

"What Dobby was revealing was simply the genius of the elves," Regulus explained patiently. "We humans destroyed their homes, their habitats. To survive, they attached themselves to us to keep their magic strong. They began using humans as batteries. And they had an inexhaustible supply. We are only fortunate that they are benign beings. Had they been violent and malicious, they could wipe us out before we even had chance to respond."

"But why don't they just strike out and forge new habitats?" Hermione asked.

"Because the magical world has gotten used to having its slave-culture," Regulus replied, darkly. "And they aren't about to give it up without a revolution. The bond between wizard and elf can be hugely rewarding and fulfilling, for both of them. But some unscrupulous souls have abused the amiable Elfish nature … have turned those bonds into binds. And it is not in Elfish nature to rebel … they are docile … and they have been bred to be that way."

Hermione gasped as the horror of the understanding settled on her. "Is … is this Horizon again?"

"No, but it could be considered a sister project," Regulus returned. "Or even a parent one … for it has been in existence for far, far longer."

"So, the Elves cant rebel - or wont - because wizards have bred the notion out of them?" Hermione pondered in a near-whisper. "It keeps them in line, doesn't it?"

Regulus nodded. "And any elf who does show a strain of independent or resistive thought is ostracised and marginalised. And the dark cleverness here is that it is the culture wizards have cultivated among the elves that does the damage. Other elves turn the offending elf into a sort of pariah - and do all they can to omit them from their community and company."

"Forcing them into the wild … where they simply die!" Hermione hushed.

"Or become an easy target for a special branch of Hit Wizards, who are employed for just that sort of purpose."

"I think I want to be sick," Hermione groaned, clutching at her throat. "That's horrible, Mr Black."

"Please use my assumed name once we are out of the safety of the station," Regulus whispered urgently. Hermione nodded by way of apology. "As I was saying, magical creatures need only a source of natural magic to renew themselves. Humans were just the easiest resource for the elves to tap ... in their desperation to avoid extinction. But we have a warren of wild elves back at the Halcyon Gardens. I'll take you to meet them, if you like."

"Oh, will you?" Hermione cried, brightening up. "I'd really like that! I'm just terribly worried about all that I don't know … I was on the verge of summoning Dobby myself! And he would have revealed the location of the estate if he'd come!"

"No, that wouldn't have happened," Regulus soothed. "The Gardens are protected by ancient Celtic magic. A House-elf would have had no more chance of locating it than a wizard. If Dobby had tried, the magic protecting the estate would have simply returned him to his original location. In any case, Albus wouldn't have allowed Dobby to be used in that way, had I granted him permission to come and go. He is too well known as Harry Potter's elf … the level of monitoring on both of them is off the chart!"

"It is?" Hermione breathed, slightly overwhelmed.

"Of course," Regulus revealed. "We know that there are at least three students at Hogwarts that the GR had enlisted to track Harry's every move … and one Professor that we are certain of. They even coerced one of the Hogwarts elves to shadow Dobby."

"How do you know all this?"

"Because," Regulus began with a smirk. "We are also intently monitoring Harry … as well as those who are tracking him. That is why I wanted to come here. I have to speak to some of my contacts, just to confirm what you said about Dumbledore."

"But what if he got to them, too?" Hermione argued. "To cover all his tracks?"

Regulus pondered that with a fraught expression. "If that was true then his deception goes deeper than either of us could imagine. Wait here … and put this on."

Regulus reached into his cloak and handed Hermione a flowing, silvery garment. She looked at it and lost her breath.

"An Invisibility Cloak!" she hushed.

"Yes," Regulus replied. "It belonged to my brother. His prankster friend, James, used to have one, so Sirius bullied our father for his own. It isn't quite as refined as James' was, but they used it to play all sorts of tricks on me when we were younger. At least I get to put it to good use now."

"W-why do I need to be invisible?" Hermione stuttered out, as the worrying thought occurred to her.

Regulus looked at her seriously. "Because … you're on a Most Wanted list, Miss Granger. Half of the Aurors in England are looking for you! Being Harry Potter's girlfriend is a dangerous hobby, didn't you know?"

Harry looked at the brick wall in front of him, still holding the ornate picture frame in his other hand. His frown was matched only by that of Minerva, who had walked into the brickwork and was now busy repairing the cracked lens of her glasses.

Clearly, neither of them had expected this wall to be there.

"What's happened to the passage?" Harry asked. "Why has it closed up?"

"We can only assume that Gringotts has been compromised," Minerva replied, bitterly. "Arngor did tell me about this emergency feature. That if anything happened at the bank that made it unsafe, all passages out of it would automatically be destroyed."

"Well that's a ballache," Harry fumed. "I was relying on this to get us to London undetected."

"So, we cant travel by Floo, we don't have Apparition licences, and the Hogwarts Express has been commandeered by the Grey Robes for reasons unknown, but that we can guess will suck dragon eggs," Neville grumbled. "You'll be swimming to London at this rate, Lion-born."

Harry turned his scowl on Neville. "If you call me that again I'm going to kick you right up the arse! I love Luna, but I might have to garrotte her for that!"

Just then, the girl herself entered the room. "I've come to keep watch," she announced brightly. Then she hitched a puzzled look onto her face as she clocked them all standing there. "Shouldn't you be in Gringotts by now?"

"Yeah, but we have a slight drawback," Harry replied bitterly. "There's a brick wall in our way."

"Oh, that is a problem."

"Yep, its put a crimp in an otherwise damn fine plan," Neville agreed with a smirk. "And what was the plan again, Harry?"

"Get out of Hogwarts, get to London, then use my other house-elf to somehow get in touch with the wizard looking after Hermione," Harry clarified.

"Off to a positive start then!" Neville teased.

"We could try breaking the wall down with a battering ram," Harry frowned. "What we need is something firm, about six feet long with a flat top. Hey - your head might do, Nev? Fancy giving it a go?"

Neville guffawed back at him as Harry tried to suppress his own grin.

"What about flying to London? Like we did last year?" Luna offered.

Harry felt the chill of the memory sweep over him as he remembered the outcome of that jaunt. It was enough to make the decision not to tempt fate at a stroke.

"No, I don't think that's a good idea," Harry replied. "Besides, it was months ago now that Voldemort recruited Charlie Weasley to head up his Air Division. For all we know there could be an armada of dragons and airborne wizards policing the assigned broom-flight corridors night and day."

"Another method of transport bites the dust," Neville moaned. "Get your budgie-smugglers and inflatable armbands, Harry. There aren't many more options left."

Harry wanted to agree, but Neville was pretty much right. There was only one thing Harry could think of

"Minerva … Brompton Road," Harry began. "The tube station connects to the regular London Underground, but Dumbledore said that it also goes all over the country."

"Yes, that's right," Minerva confirmed.

"And it operates on a similar principle to the Knight Bus," Harry went on.

Minerva nodded in the affirmative. "What are you thinking?"

"I'm wondering if it comes here … this far North," Harry revealed. "And where the closest point is that we could get on to it."

"That could work," Minerva considered. "Now that Albus has essentially installed you as the Head of the organisation. The train will come at your command."

"Well, do you know where the station is?"

"Yes!" Minerva cried excitedly. "And it is very close. It was built for temporary use, and hasn't been needed in about, ooh, seven years, but it should still be there."

"Seven years?" Harry queried. "What was it last used for?"

Minerva smiled with twinkling eyes. "To transport the pieces of a giant chess set - and a huge genus of Devil's Snare - into underground chambers beneath Hogwarts. I think you know the way to access it from this side of the school, if you remember the way!"

Harry beamed widely. "Come on, Team Potterites! To the Third Floor corridor we go!"

Hermione was transferred between the firm embrace of her father, and the crushing bear hug of her mother and back again. Tears flowed, palpable relief was shared by all, then Regulus made them all a vat of tea to calm their rolling nerves.

That was when the true depth of everything hit Hermione square in the chest.

For there, piled up at the side of the drawing room, were both her and Harry's Hogwarts trunks. Hermione put down her tea and hurried over to them, before she began ransacking her assorted possessions.

"What is this? Why is all my stuff here?"

She snapped her head to her parents, her blazing look demanding answers.

"Harry's elf brought them here a few days ago," Catrin Granger explained. "Something was going on at the school. The possessions of - what sort of witch are you? Ah yes, Muggleborns - were being confiscated. But Harry wouldn't allow that, so sent them here for safe-keeping."

Hermione sucked in a breath, suddenly overcome with emotion. Her heart was hammering fiercely under her ribs. For even though she'd been absolutely certain of the falsehood, to hear her parents confirm it swelled her with such love that she was left light-headed with it.

Harry was alive! He hadn't been killed by the Grey Robes. She'd never been so pleased to call someone as filthy a liar as she did Dumbledore in that moment … or at least she would, once she'd remembered how to breathe properly again.

"This is disturbing news, regarding Hogwarts," Regulus breathed. "Things must be worse than I imagined."

He put down his tea and stood up, fastening his travelling cloak as he did so.

"Are you going somewhere?" asked Hermione.

"I need answers," Regulus replied. "Dumbledore has lied to me, has attempted to hoodwink the entire of Brompton Road. And now Hogwarts has been compromised to the point that Muggleborns are being stripped of their possessions. I have to find out how far things have gotten, how they have become so bad ... and why in the name of Merlin Albus is just standing by and letting it happen.

"You are safe here. I will leave you for a few hours. I'm sure you want to have some privacy with your parents in any case. Whatever you do, don't leave the house."

"I wont," Hermione swore faithfully.

Regulus nodded, then swept from the room. Hermione turned anxiously to her parents.

"Did … did Dobby say how Harry was?" she enquired firmly. "I need to know."

"He was fine, if a little angry," David Granger replied. "That little elf did tell us that much."

"I can only imagine!" Hermione replied, beaming widely and massaging her heart, which was still beating happily and furiously at all her pulse points.

"What is it, honey?" asked Catrin. "You look on the verge of a heart attack."

"It's nothing … I'm just a little overwhelmed, that's all," Hermione explained. "You see, Professor Dumbledore lied to me. He told me … told me … tried to get Lord Roth, there, to convince me that … that Harry had … died."

Even saying the words cut to Hermione like a scythe. She had to choke back a rasping sob as it caught in her throat. Catrin now clutched at her own heart … and David spat out a vicious insult, one that rhymed with blunt, and was delivered in that sort of tone.

"He did what?" David stabbed.

"Why would he do that?" Catrin added. "He always seems such a nice man."

"Oh, he can be, if he thinks it's worth his while," Hermione sniped darkly. "It makes me shudder to think why he would want you onside, though … but then again, he did help set up Project Horizon. Maybe that's something to do with it."

Colour drained from both her parents at Hermione's declaration.

"Dumbledore … was part of that?" Catrin whispered.

"Yes," Hermione nodded. "A major part. Lord Roth was one of the test subjects. He can tell you all about it … he must have forgotten something … because I'm sure I just heard the front door open again …"

And she had, but it wasn't Lord Roth who entered the drawing room a few moments later …

Harry was still thinking about Hooch and Hardbroom's Magical Flight Centre - or, as it was more commonly known, The Big Blue Tent - when the assault happened. His mind was fixated on the sky blue aerodrome at the very end of Fizzick Alley. It was huge, and had moving images of witches and wizards zooming about on brooms, of synchronised flight displays and, of course, Quidditch moves being practised. It was the first thing Harry had seen after getting off the underground train from Hogwarts, and he really missed magical flight as soon as he saw it in action.

And so he was a little distracted as he entered the drawing room of Number Twelve Grimmauld Place … and taken by surprise as a familiar chestnut-haired girl suddenly launched herself at him with as much force as any locomotive could ever manage.

"Harry!"

Harry was so fundamentally shocked to see Hermione - let alone to hear her impassion shriek of his name - that his first instinct was to shrug her off with some force, just to make sure it was really her. This just made her laugh and weep at the same time, and she mustered up more of her strength and pounced on him again. This time, she knocked him over the back of one the squashy sofas on that side of the room.

Which was handy, as it allowed Hermione to pin Harry bodily to the floor with all her weight and kiss him repeatedly, as if the habit were going out of fashion.

Harry, for his part, was glad that the sofa was blocking the display from her parents, who he could hear laughing from their seats near the hearth.

"I've missed - kiss, kiss - you! I've missed - mwah, mwah - you so much!" Hermione breathed, through peppering her lips to every part of Harry's face she could reach. "Never leave me - mwah - like that again - mwah!"

"I promise, I wont," Harry replied back, capturing Hermione's mouth with his own when she was kissing that part of his skin. "I love you. I'm sorry I sent you away. I love you, Hermione."

Hermione snapped her head up and scowled at him playfully. "Hey - you don't get to say it first! That's cheating!"

"Well, your lips were a little busy," Harry grinned back. "And I don't remember giving you permission to stop!"

Hermione laughed and placed another raft of kisses to Harry's mouth, which was swelling from the pressure. Eventually, they broke apart and just held each other tightly a moment.

"Perhaps we should get up," Harry whispered into her hair. "Your parents are watching."

"Let them watch," Hermione breathed back. "I've missed you so much I don't care if they watch us having sex at this point!"

Harry laughed and squeezed Hermione tight to him. He knew what she meant … even though he hoped she was just lost in the moment and exaggerating. Just then, Minerva coughed pointedly above them. That was Hermione's cue to ease herself up from Harry's embrace.

"Professor," Hermione began, flushing deeply. "I didn't know Harry had brought company."

"And I didn't know you could kiss like a porn star!" Neville joked, stepping out from behind Minerva.

"Nev, Hermione's parents are here!" Harry hissed as he regained his feet.

"Yes and we saw it all!" David laughed.

"Or, at least, we heard it!" Catrin grinned. "The pitter-patter of tiny lips at any rate!"

"Mother!" Hermione admonished in a scandalised tone.

But none of them were in the slightest bit abashed. For Harry and Hermione had fallen into an arm-in-arm pose as though it were the most natural thing in the world - his around her waist, hers a little higher up just beneath his shoulder blades. The little circles Harry's palm was drawing on the small of Hermione's back were making her a little hot and flustered, but she rather thought that if he tried to stop she might hex him for the very notion.

They were so close they were practically fused at the hip. But it was just right for the both of them, the place that both should be. This being apart nonsense was just that … utter nonsense. And in that moment - as though they were sharing thoughts as well as personal body space - they both decided that they couldn't separate ever again.

So something had to be done about that. And it was Luna who provided the obvious solution

"Hello Hermione," she chirped sweetly. "How's Celesca?"

"She was very well when I saw her yesterday, but I'm sure she misses you like crazy," Hermione answered.

Luna blushed to the roots of her hair. "I'm sure she does, if she feels anything like I do. Can I ask you something? It's quite a big favour."

"Ask away."

"Can you take me back with you, when you go?" Luna asked cautiously. "Hogwarts isn't safe anymore and I'm not happy there now. And I miss Celesca more than I can explain. Please, don't make me go back to Scotland."

It was Harry who answered. "None of us are going back."

Hermione snapped her head to him. "What? You're leaving Hogwarts?"

"Yeah," Harry confirmed. "I think my time in formalised education has come to an end."

"Mine too," Neville agreed enthusiastically. "I'm coming to. Maybe me and Enola can … you know … make some magic in nature!"

Harry and Hermione laughed at that. Minerva was a little less impressed.

"But where will you go?" she asked.

"I own a huge swathe of land in South Wales," Harry revealed. "I inherited it when my godfather's estate passed to me. I think it's time I claimed it."

"Harry!" Hermione cried excitedly. "Lord Roth's estate is in Wales! I'm sure he can help you find the land of your fathers."

"You do know who Lord Roth is, don't you?" Harry queried.

Hermione nodded. "But we cant use that name in the wider world. It's too dangerous."

"I can see you haven't stopped learning in our time apart," Harry teased. "What else have you found out?"

"Nothing much," Hermione replied with a little smile. "Oh, apart from the location of your mother's Alchemist's Cell, of course!"

She let her matter-of-fact tone rock Harry's foundations a moment before bursting out in laughter.

"You should see your face!" Hermione teased. "It's a picture!"

"You … found the Cell?" Harry breathed. "How?"

"Because it's not a place, as such. Not one you can plot at any rate," Hermione began.

Then she turned to face Harry fully, placing his hand over her heart, and mimicking the action with her own palm on his chest. Harry tried not to let his body react inappropriately to the fact that he was touching Hermione's breasts. He was reasonably confident that her parents wouldn't overlook that particular indiscretion.

"The Cell is nowhere, yet it can be everywhere and anywhere," Hermione began in a reverent whisper. "But the way we get into it is always the same. And it's via these."

Hermione pressed her hand hard against Harry's sternum, and closed a fist around his own palm as she squeezed his digits tight into her warm flesh, against her throbbing heart, which did nothing to stop the tide of blood rushing below his belt-line.

"I'm not sure I get that," Harry hushed back.

"I know, but I'll show you everything, I promise," Hermione breathed. "I think I understand now. I'll explain it all. Trust me. You're safe now, this wont hurt you, nothing will … I wont let anything hurt you ever again. And I'll have to answer to your mother if I do!"

"You … you've seen my mother!"

"Seen and spoken to," Hermione confirmed. "In fact, part of my coming to London was to try and find a way to do that easier."

"How?" Harry queried.

"I … er … hadn't gotten that far," Hermione confessed. "I was just, sort of, winging it."

"Harry - what about your cloak?" Neville suddenly piped up. "Didn't you say it contained a part of your Mum somehow?"

"What!" Hermione breathed. "Harry? Is that right? Is that cloak a … a Horcrux?"

Harry nodded in confirmation. "It was the Standard of Gryffindor. Voldemort was going to use it for his last Horcrux, but when my mother thwarted his attempt to kill me, her soul took it in his place. That's how I was able to hear her. She connected to me through it."

"Then we have to get it!" Hermione cried. "We can access her Cell anywhere with a connection like that! Er, honey … where is the Cloak?"

"It's in my Gringotts vault."

"Harry? I thought we decided that Gringotts had been compromised? Wasn't that why we took the special train to get here?"

Luna had pointed out the blatant truth, as was her way. Harry slapped his head in his stupidity. Hermione came to her senses first.

"A train? You came here by train?" she asked Harry.

"Yeah. I'm the Head of a group called Brompton Road now. I've been busy too, you know!"

"Brompton Road! But that's how I got here!" Hermione whooped. "That's great news, Harry!"

"It is?" Harry replied, scratching his head. "Why?"

"Because it gives us access to our Ratway … and a way to escape," Hermione grinned. Then she took charge. "Right … Mum, Dad pack your things. We're leaving. Professor McGonagall, can you help them with magic, please? And before you think about arguing, you're coming with us. End of story."

Minerva opened her mouth to argue, then decided against the idea after seeing Hermione's expression was sterner than her own. She was out-frowned on the issue.

"Luna, Nev, you go and find Harry's house-elf, Kreacher," Hermione bossed. "Tell him the situation and send him to get Dobby and bring him back here. Tell him to be discreet."

"And what about me?" Harry quirked.

Hermione turned to him with the steeliest expression of them all. "You and I are heading to Gringotts. I have an Invisibility Cloak now, so get yours out and lets go. We have a Final Withdrawal to make from the bank. Then we can all get the hell out of here!"

Author Note:Hey everyone, I hope you've enjoyed the recent updates and the story in general. I'd like to thank everyone who has taken the time to like/favourite/give kudos etc (all depending on where you're reading this!) throughout this story and for supporting me in the writing of it. It's always great to get positive feedback and thankfully the overwhelming response has been good, so thank you very much.

As of now, I feel this is the right time to bring this story to an end. As a Sixth Year fic I think it's a natural finish point. The confrontation and resolution of the bigger story arcs are enough for an entirely new standalone fic, and as this story is already over 180k words in length it's getting a bit too long now to keep dragging out.

So this brings Alchemist's Cell to a conclusion in my mind. Also coming to an end is my Potter fandom writing career. At time of writing I have no thoughts about writing new Potter material, which would include any sequel to this story. I intend to focus on my Potter/His Dark Materials Crossover, before leaving behind the Potter fandom for good and exploring new areas. I don't feel I have much left to offer the fandom, and the tag of 'Dark Harmony Writer' that Lost Horcrux tarred me with doesn't seem to want to leave me, which means my audience will always be limited and my reputation fixed with too much of a negative slant for my liking.

So I'd like to take this opportunity to say thank you to all the readers who have supported me over the years and enjoyed my stories. I have accumulated over one million combined reads, which I am proud of, and I like to think I've entertained a handful of people at least! Its not bad going for a limited wordsmith like myself.

So thank you very much, keep shipping Harmony, and toast me a Butterbeer from time to time!

Thank you.

Additional: Aug 2020. The Muse bites again and I am plotting a sequel. I have not yet decided if i will post it here. Look for me on Wattpad and AO3 if you want to find it when I eventually get around to posting it,