“Severus, please fetch me the strongest Truth Potion you possess, and then go down to the kitchens and bring up the house-elf called Winky. Minerva, kindly go down to Hagrid’s house, where you will find a large black dog sitting in the pumpkin patch. Take the dog up to my office, tell him I will be with him shortly, then come back here.”

If either Snape or McGonagall found these instructions peculiar, they hid their confusion. Both turned at once and left the office. Dumbledore walked over to the trunk with seven locks, fitted the first key in the lock, and opened it. It contained a mass of spell-books. Dumbledore closed the trunk, placed a second key in the second lock, and opened the trunk again. The spellbooks had vanished; this time it contained an assortment of broken Sneako-scopes, some parchment and quills, and what looked like a silvery Invisibility Cloak. Harry watched, astounded, as Dumbledore placed the third, fourth, fifth, and sixth keys in their respective locks, reopening the trunk, and each time revealing different contents. Then he placed the seventh key in the lock, threw open the lid, and Harry let out a cry of amazement.

He was looking down into a kind of pit, an underground room, and lying on the floor some ten feet below, apparently fast asleep, thin and starved in appearance, was the real Mad-Eye Moody. His wooden leg was gone, the socket that should have held the magical eye looked empty beneath its lid, and chunks of his grizzled hair were missing. Harry stared, thunderstruck, between the sleeping Moody in the trunk and the unconscious Moody lying on the floor of the office.

Dumbledore climbed into the trunk, lowered himself, and fell lightly onto the floor beside the sleeping Moody. He bent over him.

“Stunned—controlled by the Imperius Curse—very weak,” he said. “Of course, they would have needed to keep him alive. Harry, throw down the imposter’s cloak—he’s freezing. Madam Pomfrey will need to see him, but he seems in no immediate danger.”

Harry did as he was told; Dumbledore covered Moody in the cloak, tucked it around him, and clambered out of the trunk again. Then he picked up the hip flask that stood upon the desk, unscrewed it, and turned it over. A thick glutinous liquid splattered onto the office floor.