Severus Snape shot Dumbledore a look of surprise.
The operation had gone far more smoothly than he had anticipated.
He had expected a fierce struggle—after all, Slughorn was an exceptionally capable old wizard. Extracting the truth from a master of Occlumency and a Potions expert would have been no easy task either.
And yet, after barely ten seconds of hesitation, the man had decisively surrendered and revealed everything he knew.
Albus Dumbledore, however, did not appear the least bit astonished.
"So what mission did Tom assign you at Hogwarts, Horace?" he asked calmly.
"There was only one mission… to kill you!" Slughorn shrugged. "Another Hogwarts professor and a student were given the same task, though I don't know who they are. The Dark Lord didn't tell me their identities."
"How very interesting, wouldn't you say?" Dumbledore replied with a faint smile.
"…I did make a small attempt myself. That bottle of oak-aged mead—the one I gave you before Christmas—came from Madam Rosmerta at the Three Broomsticks. She appeared to be under the Imperius Curse."
Slughorn quickly added, "Of course, such a crude method could never have harmed you. I have every confidence in you, Albus. In a way, it was a warning—so you wouldn't grow complacent…"
"That brings us, unfortunately, to poor Sybill," Dumbledore said with quiet regret. "As you know, she has never been able to resist a fine mead. While she was in my office complaining, I stepped out briefly to see a student. In that short moment, she uncorked the bottle and took a small sip…"
"Poor Professor Trelawney!" Slughorn echoed sympathetically, before his expression shifted abruptly. "Wait—does that mean… I'm responsible for her poisoning?"
"Yes," Dumbledore nodded. "Attempted murder. The circumstances are not especially severe, and your confession has been prompt… but a year or two in Azkaban will likely be unavoidable."
"Azkaban…" Slughorn shuddered visibly. "You're joking, surely, Albus… my old friend…"
"Perhaps," Dumbledore replied lightly. "Is there anything else you wish to add, Horace?"
"But there truly is nothing more!" Slughorn protested, sounding increasingly anxious. "The Dark Lord knows our relationship. He would never trust me completely. If not for the shortage of capable followers under his command, he would never have sent me to Hogwarts in the first place."
"He only demanded every detail I knew about that boy—Jon Hart—and forced me to accept the mission. I'm merely a decoy. If he truly meant to strike at you, he would certainly have other plans."
"I agree," Dumbledore said, stepping forward and gently patting Slughorn's shoulder. "I believe you. I don't think you've spoken a single lie."
Slughorn visibly relaxed.
"Then how are we to determine where your loyalties truly lie?" Severus Snape spoke at last, his voice cold and measured. "Are you on the Dark Lord's side—or ours?"
"Of course I stand with you!" Slughorn exclaimed, his face flushed. "I was coerced! Under those circumstances, I had no choice, Dumbledore! He was once my student—I know how powerful he is. I still wish to live another few decades…"
"And how can we be sure you won't betray us again and return to the Dark Lord?" Snape asked icily, lifting his wand slightly.
"Calm yourself, Severus… please!" Slughorn panted. "When I was recuperating at St. Mungo's, the Dark Lord sent someone to approach me. Yet I still chose to return to Hogwarts. In truth, even before Halloween, when I heard that the tower at Nurmengard had collapsed, I turned my back on the Dark Lord in my heart…"
"What does that have to do with the tower at Nurmengard?" Snape frowned.
"Severus, you are still rather young," Slughorn replied, shaking his head. "Our generation is dwindling. Very few people truly understand what happened back then. I can only piece things together from fragments."
As he spoke, he gave Dumbledore a subtle wink.
"That Dark Lord who once dominated Europe—I am one of the few still alive who witnessed his terror," Slughorn said gravely. "Though I was young at the time."
"If he willingly confined himself within that tower fifty years ago, cutting himself off from the world, then he would never escape from it without reason after half a century. This must have been your design, Albus, wasn't it?"
Dumbledore neither confirmed nor denied.
"Especially after the news spread at Christmas that Hogwarts and the Order of the Phoenix had been attacked," Slughorn continued solemnly. "That only strengthened my suspicions. I told no one—not even the Dark Lord. I would even swear an Unbreakable Vow if necessary."
"Then why didn't you come forward and confess everything to Dumbledore?" Snape asked after a pause.
"People always cling to a bit of hope, don't they?" Slughorn replied quietly.
He turned to Dumbledore at last.
"Is this interrogation concluded, Albus?"
"Yes," Dumbledore said, lowering his wand. "I believe we can end it here."
"Then when will the Aurors—and the Dementors still loyal to the Ministry—arrive? When am I to be sent to Azkaban?" Slughorn asked earnestly. "You will speak on my behalf, won't you?"
"Perhaps," Dumbledore answered vaguely. "Though your departure for Azkaban may need to be delayed for a few days."
"Oh?" Slughorn looked up in surprise.
"There will be a minor incident at Azkaban tonight. You'll read about it in tomorrow's Daily Prophet," Dumbledore said calmly. "And Severus… I'm afraid you'll need to spend the night with Horace."