Harry Potter and the Methods of Rationality

'Yes, Headmaster!' they said, snapping upright and giving him a crisp military salute they'd seen in some old pictures.

'Hear me well! You are the friends of Harry Potter, is this so?'

'Yes, Headmaster!'

'Harry Potter is in danger. He must not go beyond the wards of Hogwarts. Listen to me, sons of Weasley, I beg you listen: you know that I am as Gryffindor as yourselves, that I too know there are higher rules than rules. But this, Fred and George, this one thing is of the most terrible importance, there must be no exception this time, small or great! If you help Harry to leave Hogwarts he may die! Does he send you on a mission, you may go, does he ask you to bring him items, you may help, but if he asks you to smuggle his own person out of Hogwarts, you must refuse! Do you understand?'

'Yes, Headmaster!' They said it without even thinking, really, and then exchanged uncertain looks with each other -

The bright blue eyes of the Headmaster were intent upon them. 'No. Not without thinking. If Harry asks you to bring him out, you must refuse, if he asks you to tell him the way, you must refuse. I will not ask you to report him to me, for that I know you would never do. But beg him on my behalf to go to me, if it is of such importance, and I will guard him as he walks. Fred, George, I am sorry to strain your friendship so, but it is his life.'

The two of them looked at each other for a long while, not communicating, only thinking the same things at the same time.

They looked back at Dumbledore.

They said, with a chill running through them as they spoke the name, 'Bellatrix Black.'

'You may safely assume,' said the Headmaster, 'that it is at least that bad.'

'Okay -'

'- got it.'

Aftermath, Alastor Moody and Severus Snape:

When Alastor Moody had lost his eye, he had commandeered the services of a most erudite Ravenclaw, Samuel H. Lyall, whom Moody mistrusted slightly less than average because Moody had refrained from reporting him as an unregistered werewolf; and he had paid Lyall to compile a list of every known magical eye, and every known hint to their location.

When Moody had gotten the list back, he hadn't bothered reading most of it; because at the top of the list was the Eye of Vance, dating back to an era before Hogwarts, and currently in the possession of a powerful Dark Wizard ruling over some tiny forgotten hellhole that wasn't in Britain or anywhere else he'd have to worry about silly rules.

That was how Alastor Moody had lost his left foot and acquired the Eye of Vance, and how the oppressed souls of Urulat had been liberated for a period of around two weeks before another Dark Wizard moved in on the power vacuum.

He'd considered going after the Left Foot of Vance next, but had decided against it after he realized that would be just what they were expecting.

Now Mad-Eye Moody was turning slowly, always turning, surveying the graveyard of Little Hangleton. It should have been a lot gloomier, that place, but in the broad daylight it seemed like nothing but a grassy place marked by ordinary tombstones, demarcated by the chained twists of fragile, easily climbable metal that Muggles used instead of wards. (Moody could not comprehend what the Muggles were thinking on that score, if they were pretending to have wards, or what, and he had decided not to ask whether Muggle criminals respected the pretense.)

Moody didn't actually need to turn to survey the graveyard.

The Eye of Vance saw the full globe of the world in every direction around him, no matter where it was pointing.

But there was no particular reason to let a former Death Eater like Severus Snape know that.

Sometimes people called Moody 'paranoid'.

Moody always told them to survive a hundred years of hunting Dark Wizards and then get back to him about that.

Mad-Eye Moody had once worked out how long it had taken him, in retrospect, to achieve what he now considered a decent level of caution - weighed up how much experience it had taken him to get good instead of lucky - and had begun to suspect that most people died before they got there. Moody had once expressed this thought to Lyall, who had done some ciphering and figuring, and told him that a typical Dark Wizard hunter would die, on average, eight and a half times along the way to becoming 'paranoid'. This explained a great deal, assuming Lyall wasn't lying.

Yesterday, Albus Dumbledore had told Mad-Eye Moody that the Dark Lord had used unspeakable dark arts to survive the death of his body, and was now awake and abroad, seeking to regain his power and begin the Wizarding War anew.

Someone else might have reacted with incredulity.

'I can't believe you lot never told me about this resurrection thing,' Mad-Eye Moody said with considerable acerbity. 'D'you realize how long it'll take me to do the grave of every ancestor of every Dark Wizard I've ever killed who could've been smart enough to make a horcrux? You're not just now doing this one, are you?'

'I redose this one every year,' Severus Snape said calmly, uncapping the third flask of what the man had claimed would be seventeen bottles, and beginning to wave his wand over it. 'The other ancestral graves we've been able to locate were poisoned with only the long-lasting substances, since some of us have less free time than yourself.'

Moody watched the fluid spiraling out of the vial and vanishing, to appear within the bones where marrow had once been. 'But you think it's worth the effort of the trap, instead of just Vanishing the bones.'