Soon, the train to Hogwarts pulled out of the station, and as expected, Ellie sat in the same compartment with Hermione again.

"It's so nice to see you again, Miss Ellie."

Hermione was obviously very happy to see Ellie appear.

"Will you still be our Defense Against the Dark Arts teacher?"

"certainly."

Ellie flipped through the book in her hands again and glanced at Hermione.

"Why do you ask?"

"Because George said the position was cursed."

Speaking of this topic, Hermione was obviously a little unhappy.

"He told me that the You-Know-Who wanted to be the Defense Against the Dark Arts teacher at Hogwarts, but was rejected, so he put a curse on the position. After that, almost no Defense Against the Dark Arts teacher could last more than a year."

"Oh...it seems there is such a rumor."

After hearing what Hermione said, Ellie seemed to remember that there seemed to be such a saying. It was rumored that the Defense Against the Dark Arts class at Hogwarts was the most teaching-intensive course... Well, to put it simply, it was quite boring.

This kind of curse might work on ordinary wizards, but if you want it to work on yourself? You'd better dream on.

Of course, Hermione didn't tell Ellie that the students at Hogwarts had already made a bet on whether she could continue to be the Defense Against the Dark Arts teacher. Strictly speaking, Ellie was not a very popular teacher at Hogwarts, because of her strictness and coldness, many students were afraid of her.

But on the other hand, she did a great job teaching the Defense Against the Dark Arts class, and compared to that nitpicking guy Snape, Ellie actually gave students a feeling more like Professor McGonagall - everyone respected her and was afraid of her, but didn't hate her that much.

"Boom boom boom."

At this moment, someone suddenly knocked on the door of the box, then the door opened, and then Harry Potter appeared at the door.

"Potter? What do you want?"

Hermione was somewhat unhappy to see someone disturbing her and Ellie. Because of Ellie's influence, the iron triangle was of course broken up, and Hermione had no feelings for Harry and Ron. To Hermione, the famous Harry Potter was just a boy in the same class.

"Sorry, Granger, I need to talk to Miss Ellie about something."

Harry was a little uncomfortable facing Hermione, and Hermione frowned, looked at him, and then said nothing. Then Harry walked into the carriage, closed the door of the compartment, sat opposite Ellie, hesitated for a moment, and spoke.

"Teacher Ellie...I overheard...about Sirius."

"oh."

Ellie replied casually as she continued reading her book, but Hermione came over curiously.

"Sirius, you mean the guy who escaped from Azkaban? What happened to him?"

"He is Voldemort's subordinate, and he wants to kill me... This is what I heard from Mr. Weasley, but what I don't understand is that before I got on the car, Mr. Weasley asked me to promise not to look for Black... I don't understand, Teacher Ellie, why do I have to look for someone who wants to kill me?"

Hearing this, Hermione came over curiously, but Ellie didn't even raise her head.

"Simply because he is your godfather."

"Oh...eh?"

Hearing Ellie's answer, Harry nodded instinctively, then was stunned for a moment, and then he jumped up suddenly as if there were springs under his feet, and almost hit the ceiling of the box.

"Wait, Teacher Ai Li...what did you say? He..."

"He is your godfather and a good friend of your father."

Ellie said that she is not Dumbledore or Snape, and she never cares about spoilers.

"According to official records, Voldemort wanted to kill your parents at the time. However, your parents were not stupid. In order to protect you, they chose to use the Fidelius Charm - this is a very complicated spell. In simple terms, they would tell their address to a trustworthy secret keeper and use magic to hide the secret address in that person's heart. As long as that person doesn't tell, even if Voldemort ran to your door and pressed his face against the glass, he would not be able to discover the existence of the Potters and you."

Hearing this, Hermione and Harry both became nervous, and Harry was even more nervous.

"The secret keeper chosen at that time was Sirius Black. You see, he is your godfather. I think you should understand that this is enough to show how close and trustworthy his relationship with your parents is. But later your parents were found and killed by Voldemort. There is only one reason - the Fidelius Charm lost its effect, and the secret keeper leaked the secret to Voldemort. It's that simple."

It was only at this time that Ellie raised her head and glanced at Harry.

"So this is why, although no one has evidence that it was Sirius Black who betrayed your parents, he was the designated secret keeper at the time, and the only reason the Fidelius Charm lost its effect was because the secret keeper leaked the secret, which eventually led to him being thrown into Azkaban and then imprisoned for twelve years."

After listening to Ellie's introduction, Hermione was stunned, and Harry turned pale and trembled constantly.

Ellie did not tell Harry about the change of the secret-keeper, because only James, Lily, Black and Peter Pettigrew knew about it. If she told it, people would suspect how she knew it - this was already the most private of private things.

Of course, in Ellie's opinion, Black had it all to himself. Who told him to be so smart and change the secret-keeper? Besides, they didn't know what kind of person Peter Pettigrew was. So Ellie had no sympathy for Black being imprisoned in Azkaban for twelve years, and even wanted to laugh a little.

You deserve it.

"God, you should be more careful, Potter..."

After Hermione reacted, she looked at Harry, whose face was pale at the moment.

"Why did Sirius betray my parents?"

"You'll have to ask him personally. Maybe that's why Mr. Weasley didn't let you go to him."

The sales truck arrived at this moment. Ellie closed the book in her hand and ordered soda and cake.

"Let's have afternoon tea. We have nothing to do anyway."

Although it was afternoon tea, the atmosphere was obviously not very good. Harry looked so bad that he could hardly eat, while Hermione looked at this and that, looking at Harry without knowing what to say. As for Ellie, she ate cake and drank soda as if nothing had happened, and then picked up a copy of the Daily Prophet and started reading.

"Potter, don't worry too much. Hogwarts is the safest place. With Dumbledore here, Sirius would definitely not dare to come in to find you. Besides, Teacher Ellie is also here..."

Just when Hermione was about to go up to comfort Harry, the train suddenly slowed down and the noisy sound of the wheels gradually disappeared. This made Hermione and Harry stunned. They instinctively turned their heads to look out the window, but they did not see the familiar platform, which made them quite confused. They opened the door of the compartment and looked out, only to see other people sticking their heads out and looking around in confusion.

"What's going on?"

The two looked at each other in confusion, but before they could say anything else, the train suddenly tilted forward and stopped abruptly. For a moment, there were sounds of luggage falling to the ground and screams everywhere, and then the originally dazzling lights went out in an instant, and the interior of the entire train suddenly became dark.

At the same time, a gentle white light emerged, illuminating the originally dark compartment.

"Teacher Ai Li!"

Seeing Teacher Ellie raising her wand, Hermione and Harry breathed a sigh of relief.

"I'll go see what's going on."

Ellie and her friends were in the second carriage at the front of the train, so it was easy for them to figure out the problem. Ellie raised her wand and walked out of the compartment. Hermione and Harry hesitated for a moment, but still followed Ellie out of the carriage. Obviously, the two kids were also very curious about what happened.

After opening the door, a cold wind mixed with raindrops came over. Ellie raised her wand and got off the train. She looked around and saw that the sky was dark and gloomy. The staff of the train stood near the front of the train. After seeing Ellie and her group get off the train, one of them hurried over.

"Hey, kids can't come out!"

"I'm the Defense Against the Dark Arts tutor at Hogwarts."

Ellie waved at the other person.

"What happened?"

"That's right, that..."

After hearing Ellie's answer, the other party seemed a little hesitant, and at this moment, another person next to him looked terrified and pointed to the air.

“Here they come!”

As the screams came, everyone looked up and saw dozens of ghost-like monsters in black robes flying towards them under the dark night sky. When Hermione saw those monsters, she screamed.

"Dementors!"

"Leave it to me."

Ellie pulled Hermione behind her, then raised her wand and tapped it lightly.

The next moment, a dazzling pure white light burst out, illuminating the originally dark world.

It was a giant, pure white dragon of light.

Its size was almost the same as that of the dragon, and its huge body that spanned the sky was covered in the air. The dragon spread its wings that were big enough to cover the sky and the sun, and roared at the Dementors in front of it. Those terrifying dark ghosts were like ants in front of a tiger in front of this dragon of light, so insignificant.

“Oh my god…”

Harry and Hermione were stunned when they saw the giant dragon of light in front of them. At the same time, the windows on the train that had been closed opened one by one, and countless students stuck their heads out, staring at the scene with wide eyes in surprise.

"Well……"

Seeing this, Ellie couldn't help scratching her head. Strictly speaking, this was also her first time using the Patronus Charm, but from what she had seen so far...was it a bit too much?