"Good luck." Severus Snape said as he watched Regulus Black and Hermione Granger leave the library. The duo was going to break into Hogwarts undetected, hopefully, reach the 7th floor to access the Room of Requirements and obtain the last horcrux. The planning of this heist had taken a while, mainly because they were focused on the previous horcruxes, and they also had made plans to break into Malfoy Manor but they could abandon them now that Lucius had come through, and they've been preparing the final strike. In reality, the Hogwarts' heist as Hermione called it, was so simply it didn't feel real but it was the last big step in their plan. As he heard them apparate away, he focused back on his own work, making sure his spell would work long enough for the Aurors to arrive and process their prisoners following the downfall of Riddle.
"Hold on." Hermione instructed as she focused on where she wanted them to apparate. Side-along was uncomfortable but he used the position to get as close to her as he could anyway.
A few seconds later, they re-appeared in a dusty broken down home with a mattress on the floor and boarded up windows all around, "Where are we?" Regulus inquired.
"The Shrieking Shack." Hermione answered as they looked around to make sure they were alone.
"You're sure we won't trigger any wards?"
"Positive, the tunnel leads to the grounds, and even though it's a massive security risk in my opinion, the boundary wards don't go under ground, therefore any underground passageways are a safe way to enter the castle undetected."
"There's other ones?" Regulus probed.
"There's one from Honeyduke's cellar, probably a lot of other ones but I was most familiar with this one. I assume it wasn't boarded up because there are not entry points from outside the building, but if you know what it looks like you can apparate in. Honestly, just a anti-apparition ward and it would solve it. Hogwarts has so many security flaws between the passageways, the forest full of deadly creatures, and so many other things that could go wrong at any point." Hermione grumbled.
"Yes, we'll do the Hogwarts revolution as a third project love, let's focus on getting the last horcrux first." Regulus said as he followed her to the tunnel entrance and tried not to think about Remus Lupin turning into a werewolf in the room they were leaving.
The duo walked down the tunnel in silence, crouched down most of the way as the ceiling was fairly low and the place lacked good visibility despite their twin Lumos.
Once they reached the door, Hermione opened it a crack to shoot a spell at what Regulus knew was the base of the Whomping Willow to freeze it. They both disillusioned themselves and ran away from the tunnel and its murderous tree. While it was the middle of the night, Hermione still unfroze the tree in case someone was up and about to see it and became curious.
"Where to?" Regulus asked, facing the place he assumed Hermione was.
"We reach the middle-courtyard, there's a painting there to take us to the Grand staircase, and another one there to take us directly to the 7th floor." Hermione explained, even though they both had the plan memorised. Hogwarts was considered one of the safest places in the wizarding world and breaking into it should not be this easy.
Regulus and Hermione crept along the grounds in the darkness, having chosen a night where the moon was barely there, to allow their disillusionment charm to be more believable.
Once the middle-courtyard was reached, they went to the only hallway that housed paintings until they found the right one.
"Found him, Giffard Abbot." Hermione said in a loud whisper and they both stood in front of it as she whispered the password, "Dragon's egg."
The painting opened like a door, and the duo was able to enter a hidden staircase, once inside it closed again and they were free to climb.
The walk to the Grand Staircase took almost twenty minutes but they finally reached the other side as they stared at the back of another painting.
"Alright, we'll need to find George von Rheticus fast to avoid detection. There should be no one out in the corridors at this hour but let's not take risks. As far as I remember, it should be at the base of the stairs, on the right." Hermione said before pushing open the painting and walking towards where they hoped the painting was as fast as they could. Thankfully, before leaving the Shack they had silenced their clothes and shoes to avoid being heard, but they couldn't fully silence themselves to communicate so they had to make sure to breath as silently as possible.
They were able to find the painting quickly, and Hermione whispered another password, "Scurrilous scoundrel."
"You didn't tell me how you knew how to find all these secret passageways and shortcuts." Regulus wondered out loud.
"Fred and George Weasley." Hermione replied with a smile.
The painting opened to reveal another hidden staircase and they climbed to the 7th floor in silence, only their pants of efforts were heard. After what seemed like an eternity to Regulus, they reached the top and pushed open the painting on the other side, finding themselves on the 7th floor. He wasn't familiar with the Room of Requirement so he followed the tell-tale shimmery figure of Hermione until she stopped in front of a blank wall.
She walked three times in front of it in silence, and suddenly a door popped into existence.
"This is it." She declared as they entered the Room of Hidden Things.
"Wow." Regulus murmured as he took in the immense room filled with random objects and furniture as far as he could see.
"If something catches your eye, you can take it. I regret we never took the time to explore and maybe find hidden treasures last time, although we only have a few hours until dawn so let's get to it."
Hermione had briefed him on where she remembered the diadem being last time, so they both walked into that direction while looking around just in case.
It took almost two hours, time Regulus took to pocket a few rare books and a very old and expensive broom when Hermione wasn't looking, but they finally found the diadem next to what appeared to be a vanishing cabinet, which Hermione seemed to take great satisfaction in destroying by setting it fully on fire until only ashes were left. Regulus wisely decided not to ask why she felt the need to destroy it and filed it away for later.
She levitated the horcrux into a warded box, placing it into her bag and they started to trace back their steps, still looking around in case something interesting was stashed in this room.
"Why didn't he put any protections around this one?" Regulus wondered aloud as they walked.
"The theory was, in his arrogance, he thought he had found a secret no one else knew about when he found the room and he didn't think anyone else would as brilliant as he was."
"Based on the amount of junk accumulated in here, he was even more stupid and blinded by his own ego than I could imagine." Regulus said with a shake of his head.
"It's believed he hid it here when he interviewed for the DADA position with Dumbledore, at some point in the sixties, he had already split his soul five times by then by all accounts." Hermione said with a shrug.
"Shredding your own soul is pure madness." Regulus muttered.
They left the room and retraced their steps by using the same passageways, once in the Middle courtyard they heard the sounds of someone nearby and were able to see the tall figure of Hagrid walking towards them, Hermione took his hand with a whispered Run and they ran towards the tunnel as quickly as possible, trying to mask to sounds of their breathing.
Once inside the shack, they fell down on the dusty mattress and started laughing at their success and near-miss towards the end.
Once the laughing subsided, Regulus looked at the woman beside him, she had chosen to wear the tight trousers he had first seen her in, with her hair braided away from her face and with the euphoria of finally finding the last horcrux in a successful heist, he bent down above her and kissed her, to his relief she kissed him back right away and for a few minutes they lost themselves to each other, forgetting the dire reality looming above them as they finally expressed weeks of pent-up attraction and longing. They said nothing but simply looked into each other eyes, expressing their hopes and an unspoken agreement to give themselves a chance once everything was done.
They stood up, and Regulus kissed her chastely once more before she held his arm and apparated them away from the Shrieking Shack as the sun was about to rise.
"We have all of them, ready to be destroyed." Hermione announced early evening to Regulus and Severus as she had taken the morning and early afternoon to sleep after their adventure breaking into Hogwarts. Regulus had slept next to her in her bed, holding her while he also rested.
Severus did not miss the closeness of what he assumed was now a couple but didn't comment, he would enjoy teasing them once Riddle was dead and they were all free.
"When do we destroy them?" He inquired instead.
"Once the plans for the final strike are in place. As soon as Riddle is dead and his followers caged, I will be calling Alastor Moody, therefore no one on our side can be bearing the Dark Mark." Hermione announced.
Severus raised an inquisitive eyebrow at that, and Regulus rolled up his sleeve to showcase his mark-free forearm, "How?"
"It's a ritual I performed, I can do the same for you tonight. Once Lucius confirms the trap had been accepted, I'll make sure he's free as well. While Riddle is connected to the mark, we should be quick enough that he won't realise something is wrong before we have him in the room."
"Very well, let's do it." Severus nodded as he stood up and followed Hermione out of the room.
Regulus trailed behind them, not excited to see the pain he friend would go through but wanting to be there anyway.
The ritual was easier as an outsider but seeing the pain on Severus' face was not easy, although he was able to hold on longer than Regulus had, he finally fainted close to midnight. Regulus levitated him into a guest bedroom in the west wing in shades of grey, which he was sure Severus would enjoy and watched as Hermione applied the same salves she had done for him and wrapped his forearm in gauze as well.
Once it was done, they stepped out and headed towards the master bedroom, Regulus holding Hermione's weight as she started to succumb to the exhaustion of the ritual.
Two days later found the trio back in the library, waiting. At the clock chimed 6, Lucius and Narcissa Malfoy stepped out of the Floo.
Lucius looked around the occupants, nodding to Severus but freezing when looking at Regulus Black, Narcissa followed his gaze and gasped. Unlike her husband, however, she did not freeze but ran towards her cousin with tears in her eyes and hugged him tightly.
"We though you were dead." She whispered against his chest.
"I'm sorry Cissa, faking my death was the best way to work undetected. I apologise for the distress it caused." Regulus murmured back.
"Who are you?" Lucius asked, looking at Hermione instead of focusing on his supposedly dead cousin-in-law, he would leave the family reunion to his wife.
Hermione walked towards him with a tight smile, "Hermione Granger." she said as she offered her hand.
As his manners dictated, he took the proffered hand and kiss the back of it, "Of the Dagworth-Granger?"
Hermione nodded, "Yes, Hector was my grand-father and I inherited this Manor following his passing."
Lucius nodded and took a seat in the sitting area near the fireplace, his wife following him dutifully once she had made sure Regulus was healthy and whole. Severus sat down as well, followed by Regulus and Hermione, the former putting his arm over the latter's shoulder.
Lucius raised an eyebrow at the gesture but said nothing about it, "Right, I've done as Severus requested and the Dark Lord is going to visit Malfoy Manor to look at my project in two days. I will send the signal once Abraxas has been taken care of as discussed."
"Good. I've finished the cage today, and shrunk it. Once we're in place, I'll set it up." Hermione said.
"I assumed Regulus was the mastermind behind this folly." Lucius commented.
Regulus chuckled, "I'm not, if it weren't for Hermione I would be dead, literally, she saved my life and we faked my death. Contacting Severus was her idea, contacting you was his."
"I see, and why does a woman I've never heard of before wants to take down the Dark Lord?" Lucius inquired.
"You wouldn't have heard of me, and I have many reasons. The main one, however, is that letting Riddle continue as he has will bring about the destruction of our world." Hermione said in a even tone.
"How could you be sure of that?" Lucius probed.
Hermione shrugged, "Maybe I'm a Seer, or I come from the future. Perhaps I'm a genius at arithmancy and I've calculated the consequences of his actions, the how doesn't really matter. Getting rid of the madman does."
Lucius snorted, "Right, I'll remain cautious. What's your plan once it's done? The cage you've mentioned is meant for all his marked followers and I'd rather not be thrown into Azkaban for my father's decisions."
"Do you think you'll be summoned at some point before the agreed meeting?" Hermione inquired instead.
"No, he's abroad until a couple of hours before he is to come to the manor so there's no chances I'll be summoned. Why?"
"To remove your Dark Mark. Therefore you won't get caged, or arrested." Hermione explained and both Regulus and Severus rolled their sleeves to showcase their forearms.
"Yes, I'll do whatever it takes to be free of that taint." Lucius exclaimed, his hope to be free and give Narcissa the family she desired winning against the caution and distrust he harboured for the Granger girl.
"Does Mrs. Malfoy also has one?" Hermione asked.
"No, I do not." Narcissa Malfoy replied with a sniff, clearly implying what she thought of getting marked.
"Very well. The ritual isn't long but you will likely faint, will it be an issue if you don't go back to the manor tonight?"
"No, it shouldn't be. I told father I would be out with Narcissa but didn't specify where so he'll assume we're in our Paris townhouse or something like that." Lucius said with a shrug.
"Follow me." Hermione said, and the group trailed behind her as she went down to the basement and the ritual room.
Under the eyes of everyone, she instructed Lucius to stand in the middle of the pentagram and placed ingredients at all five points.
"What are the ingredients?" Lucius asked.
"Unicorn hair for purity, moondew to wash away impurities and negative energies, phoenix ashes for rebirth and renewal, dragon's blood resin for cleaning, and gillyweed essence to clean and refresh the air inside the pentagram. Once we're ready, I'll chant the ritual and then use fiendfyre to end it." Hermione explained.
Lucius stood still, shoulders back and straight. While the ritual itself was expected, the mention of the cursed fire was making him tense and apprehensive. He knew getting rid of the blasted mark would hurt but he hadn't thought it would be burned away quite literally, although until tonight he hadn't even considered it was a possibility at all.
Once all the ingredients were placed, Hermione stood in front of him and he nodded his readiness.
"Ab maleficio obscuro te absolvo,
Sanguinem tuum purifico, spiritum tuum libero.
Signum maledictum nunc evanescat,
Lux sancta te protegat,
Cor tuum a tenebris liberetur.
Nunc et in perpetuum, ab omni malo purificare."
Once she was done chanting, Hermione squared her shoulders and whispered a soft Fiendfyre.
The pain was immediate and devastating, Lucius couldn't move as Hermione had cast an immobulus spell on him but while he remained standing up, he fainted from the strain anyway.
Severus took the charge once Hermione had cancelled the cursed fire, and levitated Lucius to another guest room next to his own, where he placed him on the bed and put the salves Hermione used on Regulus and him. Once his forearm was wrapped, Narcissa took over, changing his clothes to an appropriate sleeping attire made in light blue silk and tucked him into the bed.
Everyone said a soft good night to each other as they left the room, Regulus choosing to share Hermione's bed once more.
Once Hermione fell asleep in his arms, her back to his chest, Regulus felt himself relax for the first time in a long time. While he knew taking down Riddle wouldn't be easy, they had enough advantages to feel secure in their victory. Even though he hadn't talked about their relationship with Hermione yet, he felt confident she would agree to a courtship and reciprocate his feelings. Kissing her had been a revelation and he found opportunities to do it every time he could when they were alone. Severus was right, he did love her but falling in love with Hermione Granger had been the easiest thing he had ever done.
A/N - Final strike next chapter, likely another one to follow to tie up the loose ends and then the epilogue
The chant is the same as the one in chapter 3 but here is the translation anyway:
"From the dark curse, I absolve you,
I purify your blood, I free your spirit.
Let the cursed mark now vanish,
May holy light protect you,
May your heart be freed from darkness.
Now and forever, be purified from all evil."
The secret passageways and their passwords come from various canon places in the HP universe, taken from the harry potter DOT fandom DOT com website.