After confirming that Professor Lupin wouldn't wake up, the four exchanged what they knew about Sirius. Harry couldn't help sighing. "I really don't want trouble, but why does trouble always come looking for me?"
They talked the whole way, while Professor Lupin slept the whole way. He was sleeping so soundly that Ron couldn't resist checking whether he was breathing.
It was dark outside now, and the four could feel the train slowing down. Ron put down the candy in his hand. "We're finally getting there. I'm starving."
"Wait, the timing's wrong."
"Then why have we stopped?"
The train jolted, then ground to a complete stop. All the lights went out, plunging everyone aboard into darkness.
Harry looked outside. He could feel the temperature dropping. In the faint light, he saw a tall, cloaked figure floating toward them. A grayish-white hand protruded from beneath its cloak, gleaming eerily. It was covered in slime and blotches, like a corpse bloated from soaking in water.
"Harry! Get over here, away from the door. Ron, you too!" Bing Huan sensed an overwhelming malice. It wasn't particularly strong, but it was utterly pure.
This monster definitely wasn't human. At least, Bing Huan had never seen a human whose only instinct was to do evil. Harry was a step too slow. The monster came close and took a deep breath.
In an instant, a bone-chilling cold swept over them, and frost flowers formed on the windows. Harry, closest to the monster, felt the cold seep into every inch of his body.
It was as if he were trapped in a deep pool, with people constantly dragging him toward the bottom. He could still hear distant screams and pleas for mercy. It was as if his life with the Dursleys before he turned eleven had become a hundred times more painful.
The others saw only the monster approach Harry and inhale. Harry immediately rolled his eyes and began to tremble all over. Wisps of white, mist-like substance were drawn from his body and absorbed into the monster.
"Dragon Flame!" Bing Huan drew Crimson Trail and struck. The blade passed through the monster without resistance. He had to pull back in time, or he might have damaged the train.
"No physical body? A ghost?"
With no time to think, Bing Huan pulled out every talisman he had that could restrain ghosts and monsters, but none of them worked. He forced himself to calm down. The creature before him was clearly some kind of unusual evil spirit; perhaps only a specialized method could affect it.
The only unused option he had was Lightning Magic, but he hadn't cultivated righteous qi, so it wouldn't be especially effective. He'd have to use something with massive destructive power, and in a cramped compartment like this, he'd only end up hurting his friends first. That left only... Life-shortening Summoning.
Bing Huan glanced at Harry, whose face was growing paler by the second. There was no time to hesitate. He bit his thumb and formed a hand seal.
"I humbly beseech Taiyi Lord of Tang Palace. Step upon the Lotus Platform, Mars and Black Wheel. Wield the Demon-Subduing Seven-Star Sword. Sever the myriad ghosts in the shadows... Your disciple devoutly beseeches you: Marshal of Tang Palace, descend here. Divine Soldier, Urgent as the Law."
Just as Bing Huan was about to press down, someone grabbed his hand.
"Stay calm, child."
Professor Lupin had woken at some point. His voice was hoarse, and his wand was pointed straight at the monster.
"Expecto Patronum!"
A silver-white light shot from the tip of his wand. The monster fled the moment it saw it. Harry stopped trembling, and the temperature in the compartment rose again.
They helped Harry onto a seat. He soon woke up, and Professor Lupin handed everyone a piece of chocolate.
"Eat it. It'll help."
"What was that?" Bing Huan suddenly felt a sense of urgency. He realized he still had a serious weakness: he was helpless against this kind of unusual monster.
"A Dementor. A Dementor from Azkaban."
"I just felt..." Ron moved his shoulders uneasily, still shaken. "Like I'd never be happy again."
Hermione put an arm around Ginny, who was badly frightened.
Bing Huan: "I'm going to get some air."
Once he reached the platform outside the train, Bing Huan could no longer hold it in and spat out a mouthful of blood. He gripped the railing tightly, his mind filled with the image of himself being utterly helpless against the Dementor in the compartment.
A small hand reached from behind and grasped the one responsible for bending the railing out of shape. "Are you okay, Huan?"
Bing Huan took a deep breath, trying to calm himself. "I'm fine. The summoning ritual was interrupted, so my lifespan is safe, but I couldn't avoid internal injuries. They're minor, though. I'll be better in a few days. I'm just angry at myself for being completely useless."
Hermione shook her head. "No. If Dementors were easy to deal with, they wouldn't be guarding Azkaban. I'm the one who was truly useless. I could only watch you and Harry get hurt. Call me selfish if you want, but please don't use that again. I'm scared."
"...I promise. I won't use it again unless it's the very last resort."
The train started moving again, and Bing Huan thought of Professor Lupin's spell.
"Min, do you remember the spell that drove off the Dementor?"
"I think it was Expecto Patronum."
They both drew their wands and began practicing. They were already within Hogwarts grounds, so there was no need to worry about the Ministry of Magic detecting them. But no matter how they corrected their pronunciation, their wands didn't react at all.
"The Patronus Charm isn't a spell you can cast just by saying the words and supplying magic."
Professor Lupin's voice came from the compartment doorway.
"Professor."
Lupin patted Bing Huan on the shoulder. "Until I get my strength back, sorry for the trouble."
Bing Huan shook his head. "You're too kind. I couldn't do anything."
"You're hardly a child who can't do anything. I doubt I could withstand even one of those three moves of yours." He took out another piece of chocolate. "That last move must have exacted a price, even though you didn't complete it. Eat this and get some of your strength back."
"Thank you."
"Professor," Hermione asked from beside them, "that Patronus Charm you mentioned?"
"Oh, that. The Patronus Charm differs from other spells in two ways. Other spells are more like causing a certain effect, while the Patronus Charm is more like a summoning."
"A summoning?"
"Yes, summoning a Patronus. It's the Dementors' bane. Like a guardian, it stands between you and a Dementor, keeping it from harming you."
"Why can a Patronus hold Dementors at bay?"
"That's the second difference. A Patronus is a positive force: hope, happiness, the will to survive. Dementors feed on those very things. They make people suffer, then drain away their happiness. But a Patronus can't feel despair the way a living person can. So Dementors can't do anything to it.
"Hopefully that makes sense. When casting the spell, you must focus all your thoughts on a happy memory for it to work. It may still be difficult for you; plenty of very talented wizards can't master the Patronus Charm."
"What does a Patronus look like?"
Professor Lupin turned back at the doorway and smiled. "It depends on what's inside you. There's no need to rush. We're almost at Hogwarts, so go back."
"Expecto Patronum!"
Lupin whipped around. Bing Huan scratched his head awkwardly. "Still didn't work. Sorry you had to see that, Professor." No one but Lupin noticed the faintest glimmer of silver at the tip of the boy's wand.
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