"Griselda! To what do I owe the pleasure?"

Pomona could hear the surprise in Minerva's voice, followed by mounting irritation as she realised there had to be reasons behind Professor Marchbanks's sudden visit.

She stepped out of the hearth after the Professor.

"And Pomona." The same irritation, but this time mingled with relief. She had expected Wilhelmina, Pomona realised. How right Professor Marchbanks had been. Better, far better, that it was she, Pomona, who had broken Min's confidence.

Professor Marchbanks wandlessly Accio'ed two chairs to the desk. She sat down and pointed Pomona towards the other one.

"It's teatime."

Pomona almost smiled. Given the Professor's normal directness, this was quite an effort at small-talk. Still, small was very much the operative word.

"Quite." With a flick of her wand, Minerva Transfigured various desk objects – a paperweight, a few quills, a little sharpening-knife – into three cups and saucers in a delicate flower pattern. Violets, drawn with a botanical correctness that could win prizes. Minerva threw a sharp glance at Pomona to check that she had noticed, and, with an exaggeratedly elegant wand-flick, she Transfigured the inkpot into a steaming teapot. Then she Accio'ed some ginger newts from a tin on a shelf, and in mid-flight she Transfigured one into a little plate. Matching as well.

Why didn't she just Transfigure the biscuits, Pomona wondered, but she immediately checked herself. Gamp's Law. Didn't apply to tea, since tea is technically not a food. Just water with colour. And you can't create water, but that wasn't necessary: the inkpot. Ink, too, was water with colour. Still, it was an astonishing display of magical power. And as close to a calculated insult as hospitality could get.

Professor Marchbanks, ever the teacher, couldn't help an approving nod, but she quickly covered up the moment of weakness by remarking drily: "You didn't do much about the colour of that brew, did you?"

"Why this visit?"

No small-talk, then. And the question was aimed straight at Pomona, who sat up straight, took a deep breath, and plunged in.

"I was worried. Am worried. That's why I went to Professor Marchbanks. I've tried to be supportive, but you wouldn't let me. And sometimes you just have to dig the weed up by the roots to get results. I thought, if anyone can make you change your mind about the Headship … Why on earth do you refuse?"

"That," Minerva replied, "is entirely my own business. I'll thank you for not interfering."

"I'm not interfering with your business," Professor Marchbanks said, to Pomona's surprise. "I'm interfering with Hogwarts business, and in my long career I've earned every right to do so."

"Hogwarts is properly looked after," Minerva replied. "I've told Pomona I'd stay on for a year. I plan to leave everything just so."

"I've no doubt of that. But it seems your decision to leave may have to do with what happened during the Battle. Something of a serious nature. And …"

"Minerva, please. I'm sorry," Pomona interrupted. Sorry I felt that old battle-axe could do any good, she thought. How can she be so unfeeling?

"Min, something has happened. And I know you feel dreadful about it. Please let me help. Was it …" Pomona hesitated. Someone had to say the word out loud. "Was it an Unforgivable?"

"Whatever it was, it's my decision. Mine alone."

"No, it's not!" Professor Marchbanks snapped. "A Headmistress – and an Acting Headmistress, too – must be above reproach. If you've cast an Unforgivable, I want to know about it."

For one moment, Pomona was speechless. That was why Marchbanks had come? To accuse? To judge, even? Did the old besom think she was still on the Wizengamot?

"How dare you!" she finally burst out. "How dare you suggest that Minerva isn't fit … It's the most preposterous thing I've ever heard. You weren't even here during the Battle, and you think you can judge … You're not your bloody doorknocker; you don't have the answers, you don't have the right to ask, even!"

"She does."

Pomona stopped, gobsmacked. "Min, she doesn't. You don't have to let her …"

"She's right. I should have resigned at once. I even considered it, but I thought that, at this particular moment … The castle is damaged, Shacklebolt doesn't know which way to turn first; I felt that staying on was the best thing to do. I may have been wrong. I was wrong. I'll send Shacklebolt…"

"You'll tell me what happened. Then we'll make a cool, rational decision," Professor Marchbanks said.

Pomona stared at her, and then at Minerva, who got up, turned towards the window, and cleared her throat.

"The full facts are these: I cast an Imperius Curse on Amycus Carrow, in the Ravenclaw Common Room, just before the Battle of Hogwarts. I used it to make him hand over his wand and Alecto's, who was already Stunned at that moment. I could have achieved the same results with an Expelliarmus, or a Petrificus with a simple Accio, but I chose to use the Imperius. "

"Why?" Professor Marchbanks asked.

"Because I could. Because I felt like it."

The silence slowly grew painful. This, Pomona thought, this is what 'your mind goes blank' means. You can see the cups, and follow the outline of the violets with your eyes, and you see small particles of dust dance in the light from the window, but you can't think of a single thing to say. And right underneath all that, you relive that whole day at Headquarters, how Min helped you, how she wanted to defend you so much against Alastor's bullying that she cast that very curse, that's what it took then …

"It's not true. It's technically impossible."

Both Minerva and Professor Marchbanks looked at Pomona, who finally, slowly, began to smile.

"It didn't happen like that, Min. You didn't do an Unforgivable just because you could, since you technically can't. Not that way. See what I mean?"

Both witches remained speechless, so Pomona explained herself.

"I know a bit about casting Unforgivables myself, remember? The thing is, you can only succeed when you mean it. So when you were there, at that moment, you really wanted to cast an Imperius. And that means you had a good reason for it. A far better one then 'just because I felt like it'. What was it?"

Professor Marchbanks gave a small, satisfied nod. "Clever," she said. "Very clever. But I'll still need the full facts to judge what happened. Go on, Minerva. You went to the Ravenclaw tower. Why?"

"Never mind why; it won't change the facts. I cast that Imperius, and it was not to defend myself or to save the life of someone else. I may have told myself at the time that there was a good reason. I may still think so. But that's exactly the point: Unforgivables aren't about 'I think I've the right'. There's only one good, objective reason to cast one, and that reason doesn't apply here."

"Then why didn't you hand yourself over to the Wizengamot?" Professor Marchbanks asked.

"Because it's not just my story. Someone else is involved."

"I used to be on the Wizengamot. Tell me. Tell us. I mean it, Minerva; you shouldn't carry this on your own. You need a second opinion." Professor Marchbanks's voice sounded softer than Pomona had ever heard her.

"Can I be sure that nothing I tell you will get beyond these walls?" Minerva asked sharply. She looked at Pomona, not at Griselda Marchbanks. And that hurts, Pomona thought, but she's right. I'm the one who broke her confidence.

"You have my word, Min. I swear that nothing you'll say will get further than the three of us," she said, looking back steadily.

"Well, then. As I said, it was shortly before the Battle. I patrolled the corridors; it was my turn. Then I heard someone screaming near the Ravenclaw Common Room. It was Amycus Carrow, yelling to be let in and trying to break the door down. Now, earlier that evening, he had insisted that Filius let Alecto into the room, so she could have helped him. But she didn't. At his request I opened the door, and we went in.

"Alecto was lying on the floor. She had merely been Stunned, but he acted as if she were dead. When I pointed out that she'd be all right, he yelled that she wouldn't be after the Dark Lord got hold of her. He said that Alecto had sent for him – the Dark Lord, that is – and that the Dark Lord would think they had Potter.

"You'll understand how that made me feel. I questioned Carrow, and he said the Dark Lord had told them Potter might try to get into the Ravenclaw Tower. I couldn't see why Potter would want that – he was in my house, after all.

"I looked around, but there was no sign of Potter. No visible sign, that is, which unfortunately didn't mean everything. Potter has an Invisibility Cloak. A real one," Minerva added as she saw Professor Marchbanks's surprised look. She explained further. "A family heirloom. It had been in Albus's possession at the time James and Lily died. He passed it on to Potter at his first Hogwarts Christmas. Albus told me several years after he gave Potter that cloak. I must say it explained a lot.

"Carrow then said he'd blame Alecto's fault on the students. I told him I wouldn't allow it. He got rather insulting. In fact, he spat in my face."

Pomona noticed the way Professor Marchbanks's hands gripped her chair and wanted to say something, but the Professor gave her a look that clearly said 'Don't interfere. Let her talk.'

After a brief pause, Minerva continued her story. "It was then that Potter did spring up from nowhere. That is, from under his Cloak, of course, but until then I hadn't really believed he was in Hogwarts, leave alone in that very room.

"He told Amycus that he shouldn't have done that. As Amycus spun round – to attack Potter, I've no doubt – Potter cast a Cruciatus on him."

"Potter cast a Cruciatus?" This time Pomona couldn't help herself. Potter. A Cruciatus. It was impossible. Potter had conquered – killed, in a way you had to call it 'killed' – the Dark Lord himself with an Expelliarmus. Potter had never cast a dark curse in his life.

"He was threatened," Minerva cried, turning away from the window to face them. "Can't you see? Carrow threatened to hand him over to Voldemort; do you realise what would have happened then? To all of us? Potter had a mission, and besides, though I didn't know it at that time, Miss Lovegood was with him, too. He had to protect …"

"No, he didn't," Professor Marchbanks said calmly. "You know he didn't, Minerva. Think rationally. And you, too, Pomona. The situation, as Minerva tells it, is perfectly clear. Alecto Carrow was in the Common Room. So was Potter. Alecto must have found him, and he (or arguably Miss Lovegood) Stunned her. Then Amycus barged in. I admit that he was a threat to Potter's mission and had to be dealt with. But either Potter or Miss Lovegood could have Stunned him, too. Besides, you were there, as Potter knew, and you could have eliminated the little toad in a million ways. Let's face facts: there was no need for a Cruciatus. Only … "

The professor took a deep breath. Pomona began to feel slightly better about the whole situation. Perhaps this was what Professor Marchbanks had meant when she'd said she had been Min's mentor: that Minerva needed a judgement to be able deal with what had happened. And where she, Pomona, and Willa too, would simply say 'you were right' because they cared too much about Min to say anything else, Professor Marchbanks wouldn't. The full facts and a clear, cool conclusion. Minerva wouldn't accept anything less.

"Only", the Professor continued, "and I'd never thought I'd say such a thing, for I do not approve of Unforgivables…"

Pomona looked at her and nearly smiled. It sounded so strangely old-fashioned, almost inadequate, to say "I do not approve of Unforgivables". But when you saw Professor Marchbanks, tiny, indomitable, fierce Professor Marchbanks, you realised just what her disapproval meant. That there was such a thing as true decency. That it mattered. And that in her cool, rational way, she too was fighting for Minerva tooth and claw.

"But in this case," the Professor went on, "I can almost understand the boy. What he did was utterly wrong, but his motive wasn't. And I'd say that if he owes society for what he did, he paid in full. In advance, even, with all he'd been through."

She looked at Pomona and grinned. "We wouldn't have cast a Cruciatus, you and I, but we'd have come up with something highly unpleasant, too. I was thinking disfiguring spells."

Pomona found herself grinning back. "Did you ever see Carrow?" she asked. "Would be hard to find one that wasn't an actual improvement in the end. But yes, I'd have worked something out … and you're right. I mean, we wouldn't have, none of us, but … well, I know everyone goes on about the Great Potter, the Saviour of the World, but he's only a boy of eighteen, after all. Seventeen when all of this happened. I mean …"

"Exactly!" Minerva said, nodding to Griselda. "And you don't even know the whole situation yet. Let me explain the rest. Well, Potter stood there, and I was almost too shocked that he had shown himself to Carrow to fully realise what he had done. As far as I remember, my first words were 'Potter, that was foolish!'

"And then the boy looked at me and said 'He spat at you.' I started to say 'Potter, I'm ashamed of you,' but thank Merlin I didn't. And I nearly said 'that was very naughty' but I managed to keep that in, too."

"Naughty?" Professor Marchbanks queried, lifting an eyebrow.

'Yes. Naughty. You should have seen him to understand. His hair was all tousled – it always was, just like his father's – and the way he looked at me … that was no Saviour of the Wizarding World. That was little Harry, who was caught by his Head of House in a place he shouldn't be in, doing a thing he shouldn't do. A schoolboy thing, I mean, nothing 'unforgivable'. And at that moment, that's what he wanted. To be back in a world where the worst that could happen was that he was in for the detention of a lifetime. And that Gryffindor's chances of winning the House Cup were null and void.

"That's why he said that. He thought I meant the curse when I said 'That was foolish'. As if it's a word I'd use for an Unforgivable, but he was past realising. And he was trying to talk himself out of it.

"He'd been through hell and back again that year, he'd had already lost so much – his parents, his childhood, Albus. And he stood there, I looked at him, and I thought: if we're all very lucky, you'll end up a killer. And while we celebrate, you'll have to live with that. And I couldn't blame him for that curse. Basically, Griselda, I said the same thing as you. I called it very gallant."

Professor Marchbanks nodded. "Honouring the intention," she said. "And I agree – and I think you do too, Pomona? – that Potter should not stand trial. This wasn't an Unforgivable cast with the malicious intent of doing wrong. It was a boy who briefly broke down under stress; if anything, it should be judged along the lines of under-age magic. Wrong, but definitely not life-defining. And after everything that boy went through, and everything he did …"

"Absolutely," Pomona nodded fervently.

"Still, that doesn't explain why you should want to cast an Imperius," Professor Marchbanks went on. "What else happened?"

"He told me that Voldemort was on his way, and that Voldemort knew where he, Potter, was. You must know that there was a connection between the two of them. Albus had told me about it – he asked Severus to give him lessons in Occlumency. I'm afraid Potter failed spectacularly, and the lessons were discontinued. But Potter knew what he was saying when he told me he was aware of Voldemort's movements. If you'd seen him … he nearly fainted. I told him to flee, at once. He said he couldn't. He had to find something. The Ravenclaw diadem, of all things.

"I think that's when I realised that it would all happen that very day. Voldemort and Harry, I mean. And he was standing there, like the gallant boy he was, and even tried to reassure me.

"Then we heard Carrow. He was coming round. Obviously, I had to do something about him. I was about to cast an Expelliarmus when I thought of how Potter would feel about that Cruciatus, later. And how he would hate himself for it.

"I knew that he looked up to me as his Head of House. You may think it presumptuous, but I thought that if he'd see me cast an Unforgivable as well, it might be easier for him. He could then tell himself that even I had cast one, once. Without real need, just like him. That in a moment of extreme tension such a thing can happen.

"So I drew my wand, Imperio'ed Amycus and made him give up his and Alecto's wands. Then I tied them, and before we left I suspended them from the ceiling in a net, for good measure.

"Harry told me he was acting on Dumbledore's orders and had to get that diadem. I told him we would hold the school until he had succeeded. And then the poor boy said 'Is that possible?' If anything, that convinced me, at the time, that I'd been right to act as I did."

"Why?" Professor Marchbanks asked.

"Because of the loneliness. He just couldn't believe there was anyone at all who could help him. And in the end he had to do it alone, of course. I don't think we'll ever really know what happened in that one hour we lost him. But when he said 'Is that possible?' he simply couldn't believe that we could do something – he felt he had to defend Miss Lovegood, me, and the castle, find the diadem, and finally kill Voldemort, all on his own. All at the same time.

"I told him we teachers were rather good at magic. Told him quite drily, and it helped a little, I think. Made the world slightly more normal, McGonagall telling him off. I told him to go on his mission; we'd handle the attack.

"Then I sent a triple Patronus to the Heads of the other Houses – and you know the rest, Pomona. That's all."

Pomona nodded. When Minerva had told them of the situation, Pomona had known that they both had thought of the same thing: that day at Headquarters, when they had learned their Unforgivables. As Minerva had told Horace: now, they would duel to kill.

And there hadn't been any doubt then. Min's endless questioning and self-reproach had come later, when all was over and the dead were buried. And she had remembered her own, stern judgement: the only reason for an Unforgivable is to save someone's life. Professor Marchbanks had been right: at some point, Minerva might need the support of a friend, but right now she needed this almost cold assessment of the facts.

In the long silence that followed Minerva's words, she and Pomona both looked at the Professor. At last, the old witch looked up.

"We've agreed that Potter's Cruciatus wasn't really an Unforgivable."

Minerva and Pomona both nodded.

"But, being the young man he is, and looking upon Unforgivables in the way we know he does, there's every chance that he will, at some point, feel that Cruciatus keenly. It might cast a shadow over his life."

Again, they nodded.

"If we agree that Potter deserves a chance of normality, then I'd say that helping him to live with that moment is a form of defending him. Defending him from his own, too-harsh judgement.

And I'll even go further. An exceptional case, and Potter is nothing if not exceptional, takes exceptional measures. And if an Imperius was what it took, then you were the best person to cast it."

This time, Pomona and Minerva merely stared. Pomona was quite certain that Minerva, too, was wondering whether the fatiguing afternoon was catching up with someone of … how old, exactly?

"I see you don't get my meaning," said Professor Marchbanks, who clearly missed nothing and never even considered that she herself might be seen as the one who lost focus.

"Let me explain. When I'm at a Ravenclaw gathering, there's always a moment when someone states that the whole Gryffindor courage thing is merely an excuse for foolishness. That there are situations where a Ravenclaw can think quickly and coolly where Gryffindors merely rush in. Then they all look at me; they're always polite enough to seek my opinion."

The old witch gave them a piercing look. In the brief, deliberate silence that followed, Pomona realised that Professor Marchbanks had known exactly what she and Min had been thinking.

"And when I want to correct them – I usually do – all I have to say is 'Now, look at Minerva McGonagall'.

"If anything can help that young man, it's not knowing that a professor cast an Unforgivable. It's knowing that Professor McGonagall did, my dear. You're the best that Gryffindor has to offer. And this was, in my well-considered opinion, a textbook example of an Imperius that was necessary, and executed with a maximum of restraint. All you made him do is hand over those wands, and that may well have been the one polite gesture of Amycus Carrow's life."

So she's done it, after all, Pomona thought. She has come up with a favourable judgement. This is so clearly it. She looked at Minerva, expecting to see relief, perhaps even the beginning of a smile. But Minerva simply shook her head.

"It's good of you to say that. And I've thought of all of this myself, albeit not quite in such flattering terms. But the fact remains that I'm the kind of person who can cast an Unforgivable just because I feel I've the right to do it. I don't think that makes Headmistress material."

"The only reason to cast an Unforgivable is to save someone's life, is that it?" Professor Marchbanks asked in such dulcet tones that Pomona looked up sharply. What was the wily old thing up to this time?


"You could cast an Imperius to make a person undo some of his evil; an Avada Kedavra to defend someone. And nothing, ever, justifies a Cruciatus, isn't that what you've always thought?"


"Well, you're wrong, then, aren't you?"

"I'm not ... what do you mean?"

"I mean that we've just established, beyond reasonable doubt, I'd say, that Potter cast a Cruciatus that wasn't justified, but wasn't unforgivable, either. And tell me, by the way, in which part of the Wizarding Law is it stated that saving someone is a valid reason?"

Minerva stared at the Professor, for once speechless.

"I'll tell you where: nowhere. And there's a reason for that. The only way to deal with an Unforgivable, in legal terms, is to call it just that. Unforgivable. Any justification, any at all, merely creates the kind of legal loopholes that people take advantage of. The only thing to do is to judge, case by case, whether a curse was cast with the truly unforgivable intention to do an evil deed.

"If you're to blame for anything, Minerva, it's for stubbornness. And for pride, even. You thought you could make up the rules for Dark Curses. You can't. You were wrong in thinking a Cruciatus is always unforgivable. And you were wrong in thinking that saving someone's life is the only reason ever to cast an Imperius.

"That Imperius of yours, and I say this as a former member of the Wizengamot who has judged more curses than the two of you would know to cast, was not an Unforgivable in the spirit of the law. There is no case. When you've had time to think about it, you'll find that I'm right."

Then, slowly, the grim face of Griselda wrinkled into a smile.

"But, knowing you, you'll still want a sentence. Well, I'll give you one. I want you to remember, every day for the rest of your life, that you can be utterly wrong. I think it's about time Hogwarts is led by someone who truly realises this."

Pomona heaved a sigh of relief. If anything would convince Min that she was about to throw away the Headship for no reason at all, it would be the legal issue. As long as she got the time to consider things calmly and wasn't rushed into an instant decision. Min had spent weeks thinking of herself as a criminal, she wouldn't be able to accept these new ideas on the spot. "There's much truth in what Professor Marchbanks says, Min," she said. "I for one never knew that point about valid reasons. You'll want to think things over quietly, but I really feel there's every reason to reconsider your position."

Minerva looked from Pomona to Professor Marchbanks, who had clearly never thought of the possibility that someone might want to reconsider her judgement rather than accept it, but who nodded in agreement nonetheless.

"Yes, Pomona is right. Reconsider things. Talk them over with her. Check the law yourself, if your Scottish stubbornness feels the need." She smiled briefly at the last words.

"I will," Minerva finally said, and Pomona knew that the battle was more than half won. Now if only they could think of something normal to talk about while Minerva regained her composure.

"But there is one condition I'd like to make, before we hail you in as the new Headmistress," Professor Marchbanks added, and now she was positively grinning.

Minerva had to swallow several times before she could manage a word.

"What condition?"

Professor Marchbanks pointed at the teapot. "That you show me you can Transfigure this into proper tea. As the brew stands, it's hardly worth an "Acceptable".