Diana Greengrass watched the scene unfolding before her with visible nervousness.
Whether it was Jon Hart or Horace Slughorn, both men were completely immersed in potion brewing. Two enormous cauldrons sent scalding steam billowing into the air, and the faces of both wizards were etched with deep fatigue.
They had already spent more than a full day and night on this potion, with almost no rest in between.
"I'm finished!" Slughorn let out a long breath of relief.
Jon paid him no attention. Fully focused, he added half an ounce of powdered Occamy egg to his cauldron, followed by a small amount of powdered common rue.
Slughorn had already raised his wand, pointing it at his cauldron, and murmured softly:
"Felixempra!"
The potion inside the cauldron rapidly turned golden, like molten metal. Large drops splashed about within the cauldron, darting like golden fish, yet not a single drop spilled out. A rich fragrance wafted upward, and anyone who inhaled it felt an immediate sense of pleasure and satisfaction.
Jon did his best to ignore the scent. He smoothly raised his wand and traced a figure-eight pattern above his cauldron.
"Felixempra!"
The potion in his cauldron also transformed into drops of golden liquid. Unlike Slughorn's, it did not splash wildly, but instead gathered obediently at the very center of the cauldron.
Moreover, its golden sheen was slightly more brilliant than the liquid in Slughorn's cauldron.
...
Horace Slughorn stared at his opponent's cauldron in disbelief, then looked back at his own.
After repeating this comparison several times, he finally lowered his head in dejection and sighed.
"It seems I've lost."
An experienced potioneer could judge the efficacy of Felix Felicis purely by the depth and purity of its golden hue. Slughorn had been too distracted during the early stages of brewing and made quite a few mistakes. Even though he tried to compensate later, the flaws were still obvious.
Jon, on the other hand, had used a more ingenious potion sequence. Although he was somewhat unfamiliar with the steps, he made almost no mistakes throughout the process, giving him a slight edge over Slughorn.
Finally able to relax, Jon collapsed into his chair, a faint smile tugging at the corner of his mouth.
Beside him, Mrs. Greengrass also broke into an excited smile.
"If you truly are the successor of Headmaster Armando Dippet, then losing to you isn't such a bitter pill to swallow," Slughorn said with an easygoing expression.
Forcing his exhausted body to cooperate, Jon stood up and carefully poured the golden liquid from the cauldron, drop by drop, into a crystal vial.
After bending down to place the vial into his briefcase, Jon turned back to Slughorn.
He asked softly, "Professor Slughorn, you haven't forgotten our wager, have you?"
"No," Slughorn replied with a nod. Bound by an Unbreakable Vow, he knew full well that backing out was impossible. "Ask your question, Mr. Hart. Remember—strictly academic matters only."
"Of course." Jon smiled and nodded. "What I want to ask about is… a Defense Against the Dark Arts topic."
"Defense Against the Dark Arts?" Slughorn muttered. "I thought you'd ask something about potions." Still unaware of the seriousness of the situation, he waved a hand. "Go on, then."
"That is… how does one create a Horcrux? The complete process."
...
In an instant, the entire castle fell silent.
Horace Slughorn stared straight at Jon, his stare was lethal.
Diana Greengrass stiffened as well, her right hand quietly closing around her wand.
"I know nothing about Horcruxes! And even if I did, I wouldn't tell you!" Slughorn roared, his face dark with fury. "Get out at once, and don't ever let me hear you mention that again!"
"An Unbreakable Vow cannot be fooled. You know that perfectly well," Jon said calmly. "Even if you tampered with your memory or tried to exploit loopholes in wording, the outcome would be the same."
"Did Albus Dumbledore send you?" Slughorn asked coldly.
"No." Jon shook his head. "This has nothing to do with Dumbledore."
"Then how did you—"
Before Slughorn could finish, Jon had already taken the Slytherin locket from his pocket and tossed it toward him without even looking.
"Take a look at this, and you'll understand."
"This locket…" Slughorn caught it. This time, there was no curiosity on his face—only caution.
After opening the locket and examining it carefully, Slughorn's expression changed dramatically. For the first time since Jon had stepped into his residence, fear appeared on his face.
"Diana… could you step outside for a moment?" he said in a trembling voice.
Mrs. Greengrass glanced at Jon, her eyes filled with curiosity and concern. Jon gave her a slight nod.
...
With Mrs. Greengrass gone, only Jon and Slughorn remained in the castle.
Slughorn's face was deathly pale, while Jon remained composed and unruffled.
"Who was the true owner of this locket?" Slughorn asked, his voice shaking.
"I already told you. It once belonged to Tom…" Jon replied with a faint smile. "If he took his mother's surname, he was Tom Gaunt. And if he took his father's… his name was Tom Riddle."
Slughorn's hand trembled violently, and his wand fell to the floor with a sharp clatter.
"You're one of his people?" He didn't even bother to pick up his wand, staring fixedly at Jon instead.
"Half, I suppose," Jon answered honestly. "I did serve under him for a period of time."
Slughorn was drenched in sweat. He bent down to retrieve his wand, wiping it on his sleeve. At the same time, thin chains glowing faintly red had already begun to appear around his body.
"So this was your plan… If you lost, you'd use this to threaten me?"
"Yes. Though clearly, winning was the safer option," Jon said, nodding. "Otherwise, I couldn't be sure you wouldn't deceive me or withhold part of the truth."
He gestured toward the chains around Slughorn.
"My luck isn't bad. Professor Slughorn, I suggest you answer quickly—unless you want to be judged an 'Oathbreaker.'"
Slughorn snorted coldly, then lowered his voice.
"Horcruxes… are an extremely, extremely evil product of dark magic…"