The next memory began, again, in Snape's office. Dumbledore had clearly just stepped out of the fireplace; he dusted some stray ash from his beard as he approached Snape's desk, where the man was tinkering with a batch of what looked like Sleeping Draughts. “Good evening, Severus,” he said.

“Good evening, Headmaster,” memory-Snape replied without looking at him. “Is this urgent? I am rather occupied, at present.”

“It is, I'm afraid. I shan't take up too much of your time, I promise.”

“What is it, then?” asked the Potions master with a sigh, setting aside the vial in his hand.

“I must ask you about the potion in the cave, guarding Voldemort's locket.”

Memory-Snape looked up then, startled. “I had assumed, when we last talked of it, that you were speaking only in hypotheticals.”

“At the time, yes. The situation has changed.”

“The situation has changed in that I informed you, less than two days ago, that Death Eaters were coming to Hogwarts! You cannot – surely you cannot mean to drink it yourself?” Snape's voice had, by the end, descended into an almost-fearful whisper.

“Would I feed it to another when I could drink it myself, Severus?”

Memory-Snape slammed his fist on the desk, upsetting several flasks of his potion, one of which rolled off the desktop and shattered on the flagstones. “You,” he ground out, “are more valuable to the cause than any five wizards! There is no antidote, as you should well know!”

“Ah. I had feared as much,” said Dumbledore placidly.

“Take a house elf!” The man was standing now, spittle flying from his lips, his face contorted in what might have been rage, or loathing, or pain. “Take Potter! Take me!”

Harry started, turning to glance at the real Snape; his lips were compressed into a thin white line, and he gripped his wand as though he might snap it.

“Well,” said Dumbledore, “one out of three – I would have expected better.”

“You – Potter? Why – ”

“They will believe him, Severus. You would be surprised, I'm sure, if I told you that there are quite a few people inclined to think the best of you.”

Memory-Snape was silent for a long moment, then said, a pale echo of his usual wry self, “I suppose I can tell the Dark Lord I've done my job, then.”

“And me, too. Severus, for the last time – you must know: never once in these seventeen years have I regretted hiring you.”

Memory-Snape stared at him for one long moment, and then whispered hoarsely, “Thank you, sir.”

Dumbledore waved his good hand and Summoned a chair, which landed noiselessly behind him. He sat down directly opposite Snape, on the other side of the desk. “We have,” said the Headmaster, “one last thing to attend to before I leave.” He laid his hand over Snape's; his other dangled uselessly at his side.

Memory-Snape slowly raised an eyebrow, as though it had taken him an exorbitant amount of energy, or especial strength of will.

“The wards, of course.” Dumbledore smiled gently. “It is not unheard of for a Headmaster of Hogwarts, in times of great danger, to appoint, as a safeguard, more than one Deputy.”

For once, it appeared that Snape could think of no adequate reply. Dumbledore's eyes seemed to twinkle as he asked, “Is there anyone else in Tom's circle to whom he might consider giving the position?”

“No.”

The glow around their hands was barely noticable, and the hum of the walls around them could have been the wind, or a spell cast in the next room. The expression on memory-Snape's face, however, told Harry all that he needed to know. It was the closest to awe, or joy, he had ever seen the man.

“Take care of the children for me,” Dumbledore murmured, releasing Snape's hand. Dumbledore got to his feet; the memory blurred and faded around them, and Harry found himself propelled backwards into the Headmaster's office once more.