A/N: This is for everybody who through the series has stuck by Minerva McGonagall when, at times, she hasn't been the most obvious character to love. After the end of the series all the theories that have been made over the years will become redundant and I for one will miss that. This fic is an attempt to keep alive my personal favourite of the McGonagall theories. It won't be reveal until the end btw 

Harry had not intended to return to Hogwarts so soon.

After Dumbledore's demise the mood at Hogwarts had changed dramatically – gone was the lingering carefree laughter from those people who were determined to find some joy regardless of Voldemort's heightened terror campaign. The headmaster was gone and as much as Harry respected Professor – No, Headmistress, he reminded himself – McGonagall, he could not bring himself to go to the school, whilst she was finding her feet. Her incompetence, at least when compared to Dumbledore, was evident and he had been quite vocal about his concerns, which had left bad blood between the two of them. One of his biggest grievances had been her decision to close the school, which Harry (and several others in fact) had been quick to point out defied Dumbledore's last wishes, but she was the Headmistress and he had been powerless.

However, when Hermione had received a letter from the Headmistress offering her use of Hogwarts library for their quest Hermione had immediately accepted. She had, of course, already read a great deal of the books and certainly all of the interesting ones but McGonagall had promised Hermione use of the Restricted section as well. Hermione, it turned out, had read most of them too. McGonagall's final offer though had been too tempting to resist.

It was not common knowledge amongst students that the founders had their own library that only opened itself to the truly exceptional and those in particular need of their resources. "It's a little bit like the Room of Requirement" Hermione had explained. And so Hermione had Apparated to the gates of Hogwarts, dragging Ron and Harry with her. They had complained but when she pointed out it was Harry that was the one in need they had come quietly.

However the big problem was McGonagall could give them no indication of where the secret library was. Indeed they had not even seen her since they had arrived. And thus the trio found themselves walking down corridors they had never before seen in an attempt to find the room.

"I'm just theorising Harry! If it is like the Room of Requirement then we might need to think only about the room appearing for it to happen."

"I heard you the first time Hermione! How am I meant to think about the founders though, I don't know what they look like or anything!"

"Honestly! There's plenty of information about them in Hogwarts…"

"A History, thank you yes, we have been told about that book before."

"Ron, I'm only trying to help!"

"We've been at this for hours."

"Hogwarts is a huge place. There are hundreds of staircases and even Dumbledore himself never claimed to know about every single room in the castle."

"Yeah, well. He could have left a map of the rooms he DID know about, couldn't he?"

"Honestly Ron!"

"Accio wands!"

It had come out of nowhere and the three of them were completely taken aback when their wands went flying out of their respective pockets. They spun around and were immediately frozen by the sight of Bellatrix Lestrange.

"Bugger Merlin you lot can be tedious! And I've spent fourteen years talking to myself and the mice!"

She had not changed in Harry's estimation. Still the same talk, dark woman who had cackled wildly when she had killed her own cousin; the same woman who had tortured Neville's parents and mocked him mercilessly about it; the same woman who Hermione had always thought was vaguely familiar, though she couldn't place her at all. Through their moments of shock Bellatrix seemed to be growing bored by their slow reactions. It was Ron who recovered first.

"How did you get in?"

"I beg your pardon Weasley?"

He continued unperturbed.

"You can't have Apparated in and the barriers around the castle wouldn't have let you in. it's in Hogwarts: A History."

Hermione stared at him for several long beats, slowly a small smile formed on her face.

"You DID read it!"

"Quiet!"

With one quick flick of her wrist Bellatrix vanished their wands and began to advance on them. Harry had never felt such a coward in all his life but he reasoned it was the only thing he could do. With his seeker's reflexes he grabbed Ron and Hermione and pulled them forcibly down the nearest corridor. Bellatrix screamed in rage as her spell missed but they paid her no heed as they jumped to their feet and ran.

Next to him he heard Hermione mumble "We need to get to McGonagall's office."

Dumbledore's office! Harry thought. He felt a sudden surge of dislike for Minerva McGonagall that was completely perplexing. Rationally he knew she had done nothing wrong but she was easy to blame, after all it was on her watch that the most notorious Death Eater of the lot had slipped into Hogwarts. He felt a sudden surge from his scar and knew that Voldemort must have had big plans for Bellatrix tonight. The Death Eater in question was chasing them relentlessly through the halls and Harry briefly had to admit admiration for her tolerance levels. They were extraordinary, he and his friends were breathing heavily and moving on adrenaline but she seems indefatigable.

After what seemed like hours but was probably only five minutes they skidded to a halt before the stone gargoyle only to discover the staircase to the office already exposed.

"Oh no, she must have come here first!"

They tore up the stairs all of them shouting "Professor" and all forgetting that she now held a grander title. Upon reaching the office door they stopped abruptly – the sound of Bellatrix's footsteps had died.

"Has she stopped…?"

"Where's she…?"

"Shhhhh! We need to find McGonagall."

When they opened the door they froze immediately. They could not really have been more hocked if they had discovered their old Transfiguration Professor wearing Dobby's hats, Trelawney's shawls and dancing the meringue with Voldemort himself.

She was sat quite calmly in Dumbledore's old chair drinking tea from his bone china and reading a book Harry swore he had seen before. She looked up at their sudden appearance with mild surprise on her face, although she seemed completely unaware as to why they were there.

"What on earth is going on?!"

"Professor…"

"Headmistress, Potter!"

He was momentarily stunned by her outburst and the gleam in her eye which once again made Harry think he had done something wrong.

"Right yeah, Headmistress then. It's Bellatrix Lestrange. She's in the castle. She was chasing us but I think she's stopped."

"Probably knew we were coming to you". Ron offered by means of explanation.

Surprising them thoroughly once again McGonagall seemed to have minimal reaction to their news. She closed her book but did not put it in a position by which Harry could read the title and placed her teacup on the desk.

"Thank you for that confirmation of my ability to intimidate. It will make this much easier…much easier…" She muttered the last two words seemingly to herself.

With a supreme lack of concern for the fact a mad Death Eater was baying at her door McGonagall calmly stood and walked around to the mirror at the side of the room. Without another glance at them she began to adjust her hat. Harry could not contain himself any longer and his anger against her spilled out.

"What the hell do you think you're doing? She's out there! The woman that killed Sirius and did all that to Neville, they were you're students! You call yourself the Headmistress! What are you going to do about it!?"

Briefly, danger flashed in McGonagall's eyes when she spun around and spat, "She was my student as well!" at him, but she regained her aloof demeanour extremely quickly. All three were stunned into silence as she ignored them once more and walked back to Dumbledore's chair. Ron seemed to be slowly creeping into the corner of the room but it was Hermione breached the quiet at last with a calmer voice.

"Headmistress, something needs to be done. Bellatrix is down there, there are still other people in the castle. She seems to be afraid of you so there must be something you can do?"

McGonagall looked Hermione square in the eye and she seemed to have reverted into her lecturing voice when she said, "Actually Miss Granger, it is you three who must do something, that something be making a choice."

On their confused looks she continued.

"You can either go back downstairs and face Bellatrix or…" Her gaze did not waver from Hermione's, "…You can stay here and face me."