"This is getting ridiculous." Minerva muttered, throwing open the door to Regina's office and striding inside.

With the familiarity that had grown up between the two witches over the past few months, she dropped onto the sofa in front of the fireplace and reached for the tumbler of Firewhisky that had been placed on the end table beside it. Assuming that her friend would follow the pattern that had become normal recently, Regina had placed the glass ready for Minerva as soon as she had returned from the Great Hall after dinner. Then she had settled herself at her desk to tackle her marking before she was interrupted.

"How many today?" Regina inquired, setting her quill down and moving to join the older woman in front of the fire.

"Three; Jackson, Hendy and Franks."

Sighing deeply, the Head of Slytherin nodded thoughtfully. "Any word from Aberforth?"

Minerva shook her head. "I tried reasoning with him, but he wasn't interested."

"I don't see how we can get round this, Minerva." Regina sighed. "The Carrows are on guard outside the Room of Requirement almost constantly; either them or their little band of followers. I can't see how we can get past them."

"I think you need to make one final push. Really make Aberforth listen to you."

"I've tried." Regina reminded her, leaning heavily against the backrest of her chair and closing her eyes in exhaustion. "I really have. He isn't going to budge."

"We have nothing to lose, Regina." Minerva sighed, equally tired. "One last ditch attempt to get him to help us. If nothing comes of it then we can re-evaluate and find a new way to proceed."

Nodding, silently debating whether it was even worth the hassle, Regina stood. She gathered her cloak and headed for the door. Spotting the expression of half-amusement, half-confusion on her friend's face, the younger witch sighed deeply. "There's no time like the present, is there?"

Receiving a half-smile and a nod, Regina left her office. She didn't doubt that Minerva would still be there when she returned; waiting for news about the conversation she needed to have. The walk up through the castle was filled with tension. There were no students hiding in the shadows, attempting not to be spotted by the roaming teachers and prefects. In fact, Regina didn't spot anyone at all as she hurried through the Entrance Hall and down the steps into the grounds. The stillness was incredibly unnerving.

Letting herself into the Hog's Head, keeping her chin held high, Regina strode through the crowds of customers in their dark cloaks. The noise level dropped significantly as her presence was slowly noticed by the patrons of the bar, whispers running around the room as they glanced at each other and her, before looking away hurriedly so that they didn't catch her eyes. Regina barely noticed whether Killian and Neal reacted to the disdainful look she shot in their direction, pushing through the door to the back and letting it slam shut behind her.

"Ahhh… Ms Mills. To what do I owe this pleasure?"

"Mr Dumbledore." Regina sniffed dispassionately, looking around the dingy room for somewhere to sit. Choosing the armchair with the smallest bundle of newspapers on the seat, she moved them aside and settled herself carefully on the cushion. "I think you know why I'm here."

"By now I should…" He shrugged. "The tunnel."

"Aberforth… we need to get into that room." She almost pleaded with him to see reason. "There are so many students in there who need supplies and support. I'm not asking you to help. I just need you to allow me access to–"

"Quit your yammering, girl and follow me." The old wizard ordered gruffly.

In confusion, Regina followed as Aberforth pushed a dirty, crimson tapestry aside and revealed a small door behind it. He turned the large rusty ring and, with a low clank and then a creak, the door opened. Regina climbed the narrow, twisting staircase that was revealed behind the door and found herself in another room, the dimensions suggesting that it was directly above the one below.

Wordlessly, Aberforth jabbed his finger towards an oil painting hanging on the wall above the fireplace. A very pale, innocent looking blonde girl gazed out from the picture, her eyes seeming fixed on Regina. For a moment, nothing happened and Regina half-expected someone to come bursting in and for the whole situation to be some kind of trap. But then Aberforth stepped forward and nodded at the painting. He had a warm smile on his face that the witch had never seen there before and, quite frankly, didn't think he was capable of.

"Ariana?" He said in an almost reverent voice. "You can show her."

With a smile, the blonde turned and walked away. The brunette witch knew who the young woman was; she had read Rita Skeeter's article about the Dumbledores like everyone else in the Wizarding World.

Unlike every other time Regina had seen a figure leave their painting, Ariana Dumbledore walked away towards the back of the painting, along a long tunnel until she disappeared into the darkness.

"Is that… is that the way in?" She asked, inhaling sharply. "Is your sister going to Hogwarts?"

"Give her a minute."

"Aberforth… if this works, it'll be the only way into the castle." Regina told him seriously. "There are almost constant patrols inside the school and dementors around the boundary walls. The Carrows know everything that happens. All the old secret passages in and out are covered at both ends. There is no way to get into the castle without being spotted."

"There is now… has been for a while." He told her, grinning and nodding towards the painting once more.

"A while? What do you…?"

Ariana was walking back toward them from the back of the picture,her figure growing bigger and bigger as she got closer and closer. On one side of her, Regina could make out another person accompanying the blonde and squinted to try and work out who they might be. As they got closer, so close that only their heads and shoulders were visible, Regina allowed a smile to appear on her face.

The painting swung open on the wall, as though it was hinged on one side, which revealed the entrance to a tunnel behind it. Unable to help herself, Regina peered past the teenage boy to get a better look into the gloom behind him; broken only by what seemed to be the occasional brass lamp attached to the stone walls.

"Professor Mills!" Neville beamed at her. "Ariana said we had a visitor, but she didn't say who."

"Longbottom… how… how long has this tunnel been…?"

He laughed at her confusion. "Since a couple of days after you tipped me off and I went into hiding. Aberforth's been great at supplying us with food and drink. The Room of Requirement handles everything else."

Turning to stare irritably at the wizard who was watching in amusement, she scowled. "You knew? You let me come back here time and time again, pleading with you to allow us to use the tunnel to aid the students and you said nothing?"

"It passed the time."

Biting back a retort, knowing that they needed to keep him onside, Regina nodded sharply. "And you're all well… in there?"

"Come and see for yourself." Neville offered, stepping aside and motioning into the tunnel.

"I'm not sure that's…"

"Oh, come on, Professor." He grinned at her. "I'm sure it'll put yours and Professor McGonagall's minds at rest if you can see how we're living."

Unable to deny that she would feel much better if she could see the students' living conditions for herself, Regina smiled slowly and glanced around at Aberforth. He nodded and kicked a stool towards the fireplace, holding out a hand to help her up.

Regina climbed onto the mantelpiece, as gracefully as she could manage, before glancing unsurely at the hole behind the portrait. As Neville reached out a hand to help her through, she smiled gratefully and stepped through into the tunnel. The heels of her shoes sank slightly into the earth beneath them and she grimaced, before following the teenage boy into the darkness. The brass lamps cast a dim glow over the tunnel, causing their shadows to flicker and fall, distorted in shape, across the stone walls and ceiling.

As they walked, the passage began to slope steeply upward. Regina felt as though they had been walking for hours. Neville was talking excitedly, as though speaking to one of his peers, rather than a teacher who had believed to be a Death Eater for so long. She listened quietly, taking in everything he was saying and storing relevant bits of information to relay to Minerva when she returned to her office.

At last, they turned a sharp corner and found themselves staring at the end of the tunnel. Neville grasped her elbow gently and directed her towards another short flight of steps, ending in a door the same as the one hidden behind the portrait in Aberforth's sitting room. Neville pushed it open and climbed through in front of her. As though sensing she was slightly apprehensive, he smiled warmly.

"Don't worry… I've told them all how you saved me from the Carrows. It's OK."

Slightly taken aback by the sincerity and concern in his tone, Regina blinked a couple of times, before allowing herself to be pulled through into the room beyond the tunnel. She looked around in wonder, gaping slightly at the sheer size of the space.

Brightly coloured hammocks hung in their tens from the beams in the ceiling and across the balcony around the top of the walls. There were no windows, but dozens of blazing torches, similar to the ones in the tunnel, casting a cheerful light over the whole room. Looking around, Regina could see hangings representing three of the Hogwarts Houses, scattered around the room; the Gryffindor lion, the Hufflepuff badger and the Ravenclaw eagle. There was no representation of Slytherin House, not that Regina was remotely surprised by its absence at all.

"Professor?"

Regina glanced towards the small voice, finding herself under the scrutiny of many pairs of eyes. "I must say, Melanie Eaves, this is a drastic way to avoid handing in your homework."

"Sorry, Professor, I–"

"I was joking." The witch assured her gently, smiling and looking around again. She nodded towards the bookcase, stuffed with books. "I'm pleased to see that you're making some efforts to keep up with your education."

"We try." Michael Corner agreed, dropping down from a hammock and hobbling towards her. He waved off her concern before she could even express it. "I'm fine."

Lavender Brown stepped forward, offering the older woman a stool to sit on and, for a while, Regina questioned the teenagers, assessing their situation and wondering whether there was anything she could do to improve it. After a while, it became clear that the only things they were unable to gain from the Room of Requirement itself were food and drink and Aberforth was stepping in to supply that.

"I'd better be going." She said at last, standing up and smoothing down her robes. "If there's anything you need or anything I can do, anything at all, just get word to me via Aberforth."

"Thank you, Professor." Neville nodded at her seriously, holding out his hand to shake hers.

She smiled wryly, clasping his hand in hers. "Regina."

"Thank you, Regina."

To the teenagers' surprise, she walked briskly towards the hidden entrance that led into the castle, rather than the door that led back to The Hog's Head. As she reached for the door handle, several students stepped forwards, apparently intending to try and stop her leaving by that exit. Regina turned to look at them, smiling reassuringly.

"It'll be fine."

"But what if the Carrows or…" Terry Boot asked, chewing his lip.

"They'll kill you!" Neville blurted out, his eyebrows furrowed.

Regina laughed. "I'd like to see them try."