Watching the figure walking in step by step from the doorway—
"Oh my God!" Ginny covered her mouth, unable to stop herself from whispering, "How can this be?"
She wasn't the only one reacting that way.
The elderly man who had appeared at the door was someone they all knew extremely well… and yet someone none of them had expected to see here.
"Why is it Professor Dumbledore?" Ginny leaned toward Luna's ear and asked in a low voice.
Many others shared the same question, though Luna Lovegood did not seem to be one of them.
"Because Professor Dumbledore is the Headmaster," Luna said matter-of-factly, without the slightest hint of surprise. "What's strange about that?"
"Forget it, I can't argue with you." Ginny stuck out her tongue and turned back around.
By then, Albus Dumbledore had already strode up to the podium.
...
"I know many of you are surprised," Professor Dumbledore began. His voice was only slightly louder than a whisper, yet every student in the room could hear each word clearly. "After all, over a brief Christmas holiday, your Potions teacher has changed from the delightful Professor Horace Slughorn to a worn-out old man like myself…"
A ripple of soft laughter spread through the classroom, though it stopped abruptly when Dumbledore lifted his gaze.
"Of course, I can assure you that in no more than two months, I shall return Horace to you exactly as he was," Dumbledore said with a smile. "However, finding someone willing to serve as a temporary Potions teacher for only two months has proven rather difficult."
"As many of you may have guessed, your Defense Against the Dark Arts professor, Severus Snape, would theoretically have been a suitable candidate. Unfortunately, Severus has far too many matters to attend to at the moment and declined my invitation."
He paused briefly before continuing.
"So, left with little choice, I must temporarily fill the position myself."
"Though I cannot promise that I am the most suitable person for the role."
The short opening speech carried Dumbledore's characteristic humor. Students from all four houses listened intently, even those Slytherins who tried to look unimpressed.
No one took his final remark seriously. Anyone who knew Albus Dumbledore even slightly understood that, aside from opposing two successive Dark Lords, one of his greatest achievements was discovering the twelve uses of dragon blood—knowledge belonging to the highest levels of potion-making.
Looking at the students' tense and curious expressions, Dumbledore spoke gently.
"I believe your former Potions teachers have told you that you are here to learn the precise science and rigorous craft of potion-making. Potions are intricate, mysterious, and remarkable disciplines, concealed beneath countless layers. Our task is to uncover them, one layer at a time."
He looked around the room.
"So, can anyone tell me—what is a potion?"
The entire classroom fell silent.
Not because the question was difficult, but because it was so simple.
Ginny and Luna exchanged a glance, but several others had already raised their hands.
"Very good. Miss Bobbin, please."
The student he called on was Melinda Bobbin, a very pretty Ravenclaw girl.
"Professor Snape once taught us," Bobbin said confidently, lifting her chin, "that potions are magical substances created through magic. They can help us enhance our reputation, brew glory, and even prevent death…"
After finishing, she cautiously glanced at Albus Dumbledore.
Professor Dumbledore did not immediately agree or disagree.
He simply smiled faintly.
"A very conventional answer. I cannot say there is anything incorrect in it," he said. "However, I must point out that if you consider potions nothing more than magical concoctions, that is a somewhat limited perspective."
Melinda Bobbin froze, clearly at a loss.
Albus Dumbledore walked over, gently patted her shoulder, and motioned for her to sit down.
"Let us try another question," Dumbledore continued, no longer looking at her. "If, in a situation of great urgency, we required a powerful antidote, what would be our best choice? Very good, Miss Weasley—you may answer."
This time, Ginny Weasley had raised her hand before Dumbledore even finished speaking.
"Bezoar, Professor Dumbledore!" she answered without hesitation.
This was clearly the response Dumbledore had been hoping for.
"Excellent. A single bezoar can counteract many complex poisons. Five points to Gryffindor."
As he spoke, he gestured for Ginny to sit down.
"A bezoar is a stone taken from a cow's stomach—more precisely, a concretion formed in the liver and gallbladder," Dumbledore continued. "It is highly practical. Unfortunately, it requires no magic at all to produce."
The classroom fell silent once more as everyone considered his words.
"Of course, I am not attempting to undermine your former Potions teacher," Dumbledore said, his expression gradually turning serious. "But it must be said that viewing potions merely as substances created by magic is a rather narrow understanding."
"In fact, many Muggle remedies also make use of bezoars…"
He mentioned Muggles only briefly before stopping.
"Now, for the next question… Miss Weasley."
Ginny Weasley stood up again, confidence evident on her face.
"Since we know that a bezoar is a powerful antidote," Dumbledore asked with a faint, mysterious smile, "why is it able to neutralize poison?"