A/N: A large proportion of the dialogue in this chapter is taken from the book, although there had to be some changes – for instance, Flitwick was swapped for Trelawney, because in this version of the Deathly Hallows, Professor Flitwick retired and was replaced by Emma.

I just wanted to make this clear, before one of you eagle-eyed readers pointed it out ;)

"Minerva!" Regina reached out and clutched her friend's arm tightly, completely ignoring the fact that she was dressed in her tartan dressing gown. "What's happening? I heard mention of… is Potter here?"

She nodded briskly. "I've taken care of the Carrows, but they've summoned You-Know-Who. It's only a matter of time before…"

The younger witch nodded, showing her the burning mark on her forearm, which told her that Voldemort had been summoned. "I know."

"Of course…"

"Minerva…" Regina narrowed her eyes at the hesitation in her friend's tone. "What aren't you telling–?"

"Who's there?" Minerva cut across her, looking past the brunette and fixing her gaze on a suit of armour against the wall behind them.

"It is I." Severus showed himself, looking more sallow since the last time Regina had seen him which, admittedly, had been a while ago. "Where are the Carrows?"

"Wherever you told them to be, I expect, Severus."

As he stepped closer, Regina's breath caught in her throat and she felt slightly sick, worried about what was about to happen. "I was under the impression that Alecto had apprehended an intruder."

"Really? And what gave you that impression?" In response, the man motioned towards his forearm, where the Dark Mark burned. "Oh, but naturally, you Death Eaters have your own private means of communication, I forgot."

Although the comment was meant as a slight against the man Minerva believed to be working against them, Regina flinched at her words. She wrapped her hand around the mark on her forearm, squeezing as though that could remove it from her skin. Neither of her colleagues seemed to notice the movement, their eyes locked on each other suspiciously.

"I did not know that it was your night to patrol the corridors, Minerva."

"You have some objection?"

Severus tilted his head thoughtfully. "I wonder what could have brought you out of your bed at this late hour?"

"I thought I heard a disturbance." The older woman replied evenly, shrugging her shoulders.

"Really? But all seems calm." Severus looked at her curiously. "Have you seen Harry Potter, Minerva? Because if you have I must insist…"

"Serverus, I–" Regina started.

Her voice died in her throat as, beside her, Minerva raised her arm and slashed her wand downwards. Severus reacted instantly, producing a Shield Charm that was so strong that the woman in front of him stumbled backwards, wobbling as she threw an arm out to steady herself. Regina was forced to duck as the older witch aimed her wand at a torch on the wall beside her and directed it towards Severus. As it got closer it changed, becoming a ring of fire, filling the space between them and shooting viciously towards Severus.

"Minerva! Severus! Stop!" Regina ordered, trying to force an authoritative tone into her voice. "That's enough!"

The battle raged between the witch and wizard. The fire became a serpent, which became a surge of dark smoke, which became a cloud of daggers. Regina panicked as the blades flew towards her friend, flicking her wand and moving a suit of armour into their path. There were resounding clangs as the daggers embedded themselves into the barrier, rather than Severus' flesh.

"Regina!" Minerva rounded on her, eyes wide with surprise.

Nothing more was said, however, as echoing footsteps and shouts greeted their ears and both witches turned to see Professors Trelawney and Sprout hurrying towards them as quickly as they could manage. Both were dressed in their nightclothes, as was Professor Slughorn who appeared moments later, red in the face and puffing loudly.

The trio seemed to need no explanation of the situation to make up their minds about what was happening. Sybil raised her wand, aiming at Severus. "No! You'll do no more murder at Hogwarts!"

"Please, just wait. I can–" Regina shook her head, starting to explain, but it was not enough to prevent the Head of Ravenclaw's spell exploding from the end of her wand and hitting the suit of armour that was providing Severus with a tiny amount of protection.

Split seconds later, the suit of amour was springing to life, attempting to grasp the man behind it in its strong, metal arms. Giving it a firm shove, Severus sent the magically animated figure crashing into the assembled group of Professors. There was a crunching sound as it collided with the stone wall and crumbled into its component parts; hitting the floor with loud clanking sounds.

There was no time to consider the situation, however, as Severus used the momentary commotion to make his escape. At once the four witches were on his heels; Regina attempting to get him to explain and the other three furiously attempting to capture him. They crashed through the door of a classroom at the end of the corridor, just in time to see the flutter of black robes as Severus disappeared from sight through the window with a crashing, shattering sound.

"Coward!" Minerva screamed, pushing Regina aside and peering out through the smashed glass. "COWARD!"

"Severus!" Regina cried out, leaning beside her and scanning the darkness for any hint as to where he might have gone. "Sev!"

"He jumped." Minerva ground out, angrily, as two figures ran into the room. It took Regina a moment to realise who they were and her eyebrows knitted in confusion as her eyes flicked back to the woman standing beside her.

"You mean he's dead?" Harry pushed past them to peer out of the window.

The Head of Gryffindor shook her head bitterly. "No, he's not dead. Unlike Dumbledore, he was still carrying a wand… and he seems to have learned a few tricks from his master."

"That is not fair." Regina told her, fighting back the emotion that was building in her chest. "There are things that you don't–"

"Harry!" Slughorn interrupted her, grasping at his chest and gasping for breath as he entered the room. "My dear boy… what a surprise. Minerva, do please explain… Severus… what…?"

"Our headmaster is taking a short break." She informed him, indicating towards the smashed window. "I believe we need to have a conversation, Regina?"

The younger witch raised a hand to rub her eyes tiredly – both the cold tone and the use of her full name, rather than the recently more commonly used 'Gina' – instantly filling her with exhausted resignation. She sighed and then nodded, making to follow the other woman from the classroom.

"Professor!" Potter's panicked shout made them both turn and stare at him. "Professor, we've got to barricade the school, he's coming now!"

Minerva hesitated for the shortest of moments, before nodding determinedly. "Very well. He-Who-Must-Not-Be-Named is coming. Potter has work to do in the castle on Dumbledore's orders. We need to put in place every protection of which we are capable while Potter does what he needs to do."

Sybil blinked anxiously at them through her thick glasses. "You realise, of course, that nothing we do will be able to keep out You-Know-Who indefinitely?"

"But we can hold him up." The Head of Hufflepuff pointed out resolutely.

"Thank you, Pomona." Minerva nodded. "I suggest we establish basic protection around the place, then gather our students and meet in the Great Hall. Most must be evacuated, though if any of those who are over age wish to stay and fight, I think they ought to be given the chance."

"Agreed, I shall meet you in the Great Hall in twenty minutes with my House." Pomona told her, already moving towards the door.

Potter approached the Divination teacher, a thoughtful expression on his face. "Professor, I'm sorry to interrupt, but this is important. Have you got any idea where the diadem of Ravenclaw is?"

"The diadem of Ravenclaw?" Trelawney almost gasped, her already wide eyes widening further as she gazed at him. "A little extra wisdom never goes amiss, Potter, but I hardly think it would be much use in this situation!"

"I only meant… do you know where it is? Have you ever seen it?"

She shook her head wildly. "Seen it! Nobody has seen it in living memory! Long since lost, boy."

Breaking the almost uncomfortable silence that had fallen after her pronouncement, Minerva nodded sharply. "We shall meet you and your Ravenclaws in the Great Hall, Sybil."

"Minerva, perhaps I should–"

"With me, please, Regina." The older witch requested coolly, sparing her a brief glance.

Before they had reached the door, Slughorn spoke up, reminding them that he was still there. "My word! What a to-do! I'm not at all sure whether this is wise, Minerva. He is bound to find a way in, you know, and anyone who has tried to delay him will be in the most grievous peril."

Professor McGonagall shot him a disdainful look. "I shall expect you and the Slytherins in the Great Hall in twenty minutes also. If you wish to leave with your students, we shall not stop you. But if any of you attempt to sabotage our resistance or take up arms against us within this castle, then, Horace, we duel to kill."

"Minerva!"

"The time has come for Slytherin House to decide upon its loyalties." She told him bluntly, shooting a sideways look at the brunette witch beside her. "Go and wake the students, Horace."

She strode from the classroom without another word and raised her wand, ready to begin their task of protecting the castle. Regina watched her nervously, wondering what she was going to do and whether she would be allowed the chance to explain herself for attempting to protect Severus.

"Piertotum– Oh, for heaven's sake, Filch, not now!" Minerva exhaled in frustration as the caretaker appeared at the end of the corridor.

"Students out of bed! Students in the corridors!"

"They're supposed to be you blithering idiot! Now go and do something constructive! Find Peeves!"

"P– Peeves?" Filch looked absolutely horrified at the prospect.

Minerva rolled her eyes. "Yes, Peeves, you fool, Peeves! Haven't you been complaining about him for a quarter of a century? Go and fetch him, at once." As soon as he turned and shuffled away slowly, she returned her attention to the rows of statues and suits of armour lining the corridor. "And now… Piertotum Locomator!"

Every single statue in the corridor jumped down from their base, turning towards the witch who had cast the spell to animate them. Crashes, thuds and bangs from seemingly everywhere around them indicated that the rest of the hundreds of statues that decorated the castle appeared to have done the same.

"Hogwarts is threatened! Man the boundaries, protect us, do your duty to our school!" As they moved, slowly and jerkily towards the staircases that would lead them down to the Entrance Hall so that they could follow out her orders, Minerva turned to the pair of teenagers who were hovering nervously beside them. "Now, Potter, you and Miss Lovegood had better return to your friends and bring them to the Great Hall. I shall rouse the other Gryffindors."

As they nodded and hurried away, Regina reached out and laid her hand on Minerva's arm. The older witch had begun to make her way in the same direction as the magically animated statues had gone, no doubt to take control of the situation in the Great Hall. Minerva flinched at the contact and Regina withdrew her hand immediately, a cold chill going through her at her friend's reaction.

"Minerva, please, I…"

"I think it would be best if you left, Ms Mills." She said stiffly, not looking around.

"Let me explain."

"What is there to say? You protected a traitor… Dumbledore's murderer."

Regina grasped her hands, ignoring how rigid Minerva went at the action. "There are things that you don't know… things that I can't tell you, however much I want to." She shook her head, squeezing the hands that had become slightly more receptive to her touch. "I promise you that I am whole-heartedly on your side, Minerva. I am willing to lay down my life for this cause… to protect Hogwarts and the students and what is right."

Professor McGonagall squeezed her eyes closed and took in a deep, stuttering breath. "Please don't make me regret trusting you."