"Can't Polyjuice Potion mimic the signature?" Harry pressed.
Snape sighed. "Harry, I can see what you are trying to do. Having heard how very much her death distresses Draco, you are trying to find some hope for him. But there is none. It is Pansy Parkinson who was killed, and to suggest otherwise to Draco would be abominably cruel and only prolong his grief."
"All right," Harry sighed. "I'll cut it out. I just think... the Aqueous curse sounded more than a little strange. Suspicious, I mean."
"No doubt the intent was to apply the curse using Draco's wand. When the conspirators could not make it perform, they doubtless still reasoned that the curse itself would help incriminate Draco, as all of Hogwarts was aware of how vicious his anger seemed that day in my class."
Dumbledore stiffened slightly. "You have certain knowledge, Severus?"
That question confused Harry until Snape drew out of his robes a smooth wand Harry recognised as Draco's. "Not as of yet, but I believe this may be of some use to us." He held the wand out towards the headmaster, who took it in hand.
"How did you get that? Dobby was supposed to return it to me," Harry objected.
"He wanted to," Snape confirmed. "He was rather adamant, but he is in fact employed by Hogwarts these days. The magical constraints governing house-elf behaviour require him to do the bidding of staff members above students, even favourite students."
Harry frowned. "But... Dobby's not bonded to Hogwarts, is he?"
"Technically, no," Dumbledore murmured as he turned the wand over and over in his hands, staring at it almost as though Legilimizing it. "I thought better than to do that to him, especially considering that Lucius Malfoy is one of the governors. I did tell him that he must do as staff asks, however."
"I still don't like it," Harry argued. "I told him not to tell anybody, anybody, I'd sent him to look for the wand."
"He didn't tell me," Snape said impatiently. "I already knew. Harry, I have no doubt the elf is loyal to you, but he is aware both that I am your legal guardian and that I have your best interests at heart. I told him I had given you a sleeping draught and that I would return the wand as requested. Even so, I had to apply a bit of... magical pressure, we'll say, to get the wand from him."
"You didn't hurt him?"
"Don't be stupid," Snape retorted, his tone impatient. "I haven't time to argue the ethics of making a recalcitrant house-elf do as it is told."
"The circumstances of your obtaining this," Dumbledore murmured. "Tell me."
"The conspirators must have realised, when the wand would not do their bidding, that keeping it in their possession would incriminate them. Neither could they leave it in the Owlery since it would not contain the Corpus Aqueous curse Miss Parkinson suffered. Therefore, they took it with them onto the grounds. Thinking, I presume, that Draco might attempt to Accio it, they applied rather heavy anti-summoning charms to a large area of soft earth and then thrust it straight down into the dirt." Snape took a breath. "A large rock was further warded and was then placed over the site. I suspect this was to mark it in case the conspirators wished to retrieve the wand at some point. Dobby, by the way, is now standing guard nearby with strict instructions to alert me the instant anyone appears to take an undue interest in that particular area of the grounds."
"So Dobby Accioed it, is that how he got it?"
The Potions Master shook his head. "No, as it turns out, the kinship potion Draco applied to his wand renders it immune to any magic not issued by a Malfoy. Not even I could summon it, now. I doubt I could have found it, either, but as Dobby is a former Malfoy elf--"
"The kinship potion!" Harry exclaimed. "It made the wand... uh, just scream Malfoy or something? I mean, in a way Dobby could detect?"
"Yes, precisely. It bonded the wand so tightly to the Malfoy name that the elf could track it, after a fashion. And since I am a staff member, I could track him. When I reached him, he had just the moment before finished unwarding the earth so that it would release the wand."
The headmaster frowned. "This is a distressing development, Severus. If Accio will not work on the wand then perhaps, neither will Priori Incantatem."
"Agreed, Headmaster. The variant of the potion Draco used prevents anyone but a Malfoy from using the wand or applying magic to it."
"So the wand can't exonerate Draco?" Harry sighed. "If he's the only one who can cast Priori Incantatem... the Aurors won't trust the results. Or... well I suppose Lucius Malfoy could cast it but we're hardly about to trust him..."
"A sticky situation," Dumbledore concurred.
Harry looked towards where his father stood with his arms crossed. "They why did you say the wand might be of some use?"
"The headmaster at times has a sixth sense..." Snape murmured in reply.
"Unfortunately, I can get no sense of who may have handled this," the headmaster said, shaking his head. "I can't even detect you or Dobby, let alone the conspirators. It is as Harry said... this wand now simply resonates Malfoy."
Frustrated, Harry shoved his hands into his pockets. "Why did Draco have to mess about with that potion!"
"If he had not," Snape reminded the boy, laying a hand on his shoulder, "his wand would disgorge Corpus Aqueous and serve as key evidence against him."
"So you are defending his dabbling, are you, Severus?"
"No," Snape answered, his tone short. "He will most definitely be punished, and I will take greater care which books I leave within reach of my sons."
"Hey, I didn't do anything--"
One look from Snape, and Harry fell silent.
Albus Dumbledore took the scene in, his blue eyes steady as though in deep contemplation.
"What?" Harry pressed.
Dumbledore coughed ever so slightly, then popped a lemon sherbet into his mouth. For just a second, Harry wondered if the headmaster's deep pockets were charmed to constantly supply them. Then the man spoke, and Harry forgot all about sweets.
"When Severus instructed you to go sit with your brother, I rather expected you not to appreciate the phrase, all things considered."
Snape shifted on his feet. "Albus, I told you some time ago that I--"
"Yes, yes, I know what you told me, Severus," the headmaster interrupted. "You were rather vehement on the topic, as I recall. That says nothing about what Harry feels."
"I think you heard how I feel about Draco," Harry dryly murmured. Then a memory took hold of him... the headmaster, insisting Harry explain why he wanted to be adopted. "Is this more strategy for the war?" he suddenly asked. "You're trying to figure out if Draco being my brother is an asset or a liability! Or maybe you already think you know, since you did call him exactly that!"
"It should not startle you that I was dismayed by the report your friends delivered. And then to see your eye..." Albus Dumbledore lifted his shoulders. "I perhaps overreacted. At that moment it seemed quite likely that Mr. Malfoy had gone completely mad and could very well have pushed Miss Parkinson to her death."
Harry got that, sort of, but it didn't help him feel a whole lot better. "Are you apologising?" he pressed. "For assuming he did it? Because I think Draco's the one you should apologise to!"