Half an hour later,

Sirius sat on the sofa with a dark face. He heard a bad news. Peter Pettigrew had run away, or rather, he was hiding in a place no one knew and pretending to be dead.

He thought in frustration, has everything he has done been in vain for so long?

Felix picked out another book from the bookshelf, which actually mentioned a complete ancient magic. The portrait of Headmaster Phineas Black did not lie to him. The collection of books here is indeed extraordinary, although some of them were moved from the restricted area of ​​Hogwarts.

It seems that when the old man was the headmaster, he did a lot to benefit his family.

Unfortunately, things are unpredictable, and the Black family has fallen to this point...

"Have you tried the Marauder's Map?" Sirius asked suddenly.

"Marauder's Map, what is that?" Felix raised his head from the book.

Sirius said in a muffled voice: "That's a moving map that records the locations and secret passages of Hogwarts. It looks like a stack of folded parchment. We made it together when we were in school: me, James, Remus, and... Peter Pettigrew."

"The Marauder's Map can mark the traces of everyone within Hogwarts, even Dumbledore."

Felix blinked. He already knew what Lupin wanted from Filch. He said affirmatively: "This map should have been confiscated by Filch."

"We did it on purpose." Sirius curled his lips. "We were about to graduate at that time, and we were eager for someone to inherit our sacred career of pranks. So we found a suitable opportunity to attract Filch's attention and let him take the map away."

Felix nodded slightly. It turned out that there was such a past.

Sirius wondered, "Didn't Remus tell you?"

Felix whispered, "The map is lost. Filch admitted it himself."

"That old bastard!" Sirius shouted unwillingly. He slammed the wall hard and then said dejectedly, "Even if we have a map, it may not work. Peter Pettigrew can block his own name."

"Block? Did you use the Tracking Charm?"

"Not only that, the Tracking Charm, the Footprint Appearance Charm, the Name Magic, the Micro-Simulation Charm, the Concealment Charm, the Anti-Disturbance Charm, the Protection Magic, and later it also combined Transfiguration, divination and alchemy... too many things."

Felix looked at Sirius in surprise. He himself only mastered some of the spells.

Sirius explained, "At first, James brought a book on making magic maps from home. We used this book to make the prototype of the Marauder's Map. Of course, there were no moving names at that time. Later, we searched the library and found spells that could lock traces from various corners. We kept adding them. In the end, even we ourselves could hardly remember how many spells we used."

He spread his hands, "You know, when we saw the name of Headmaster Dumbledore appear on the map, we thought we were invincible. No one could escape the tracking of the Marauder's Map, because you can avoid the detection of a certain magic, but you can't prevent the second, third, fourth..."

Felix couldn't help but stroke his hand and admire. If Sirius didn't say it, who would know these things? He also saw the shadows of the other three makers through Sirius.

A stunning magical creation appeared in the hands of four students who had not yet graduated.

What happened afterwards was even more sad. The war interrupted their normal life trajectory, and if Sirius hadn't mentioned it, even the existence of the Marauder's Map itself might have been quietly submerged in history.

"How did you four divide the work?" Felix couldn't help but ask for more information. If it could be copied, it would definitely not be inferior to any known magic item.

Sirius glanced at him strangely, "James is good at Transfiguration, I am good at spells, especially silent casting. Many of the spells were added after I learned them. Remus knows everything, he glued a bunch of scattered things together. As for Peter Pettigrew..."

He frowned, and said with strong resentment, "He is more careful and checks for omissions and fills in the gaps."

Sirius paused thoughtfully after he finished speaking. He looked at Felix for a long time and said slowly, "Maybe he can't block the Marauder's Map."

"Why?"

"I remember there was a spell that only James and I knew. During the Halloween holiday in the seventh grade, we went home separately, and James found an interesting magic in the old house."

He looked at Felix, his eyes lit up, "It's a curse, or slavery magic. No, that's not accurate," he frowned, "it should be said to be a contract."

"Magic contract?"

"That's right," Sirius said affirmatively. He glanced at the door of the study and said in a low voice, "That's a very old book. The author of the book participated in the House-Elf War. The wizards at that time invented a magic that was specifically used to enslave house-elves."

Felix raised his eyebrows. He said in a tone of discussing magic, "Does this have anything to do with the Marauder's Map? Wait, I thought about it. Is it the connection between the master and the servant?"

Sirius was surprised at his sharpness. "You are right. There is a close connection between house-elves and their masters. This connection is deep in the blood and passed down from generation to generation. Now few people know it, so house-elves will never betray their masters."

That's not necessarily true...

Felix thought, relying on magic to enslave is always inferior. There is no eternal, unbreakable magic. Dobby is an example. Even the side effects of the Cruciatus Curse, one of the three unforgivable curses, have not been cracked by him?

Following this line of thought, for him, the Cruciatus Curse is actually no longer effective. Pain? He has too many ways to block the pain. The real horror of the Cruciatus Curse is that it transcends the body and reaches the deepest part of the mind.

When he protects his memory layer by layer, the Cruciatus Curse has very limited effect on him. It can be used as a disguise...

Sirius continued to say: "Think about it, no matter where the master is, he can summon the house elf. Oh, Azkaban is not possible. I tried it. It may be too far away..."

"Maybe the Ministry of Magic has collected this part of the information and made corresponding precautions." Felix guessed. "

In short, James and I tried to use part of this magic as the master's summon. The house elf sensed the master's location and added it to the map because of the contract. We designed a little trick," Sirius laughed happily, "When you walk into Hogwarts, you sign a temporary blank contract by default. It has no binding force. You can even refuse it!"

Felix smiled and said: "The premise is that the person finds this contract, but I think you will not let it take effect at all, but in a state of waiting..."

"That's it!" Sirius said excitedly, he let out a strange cry: "Completely harmless, but your location will be exposed."

"The best thing is that Peter Pettigrew didn't know this. A few days after returning from the Halloween holiday, we decided to leave the map at Hogwarts and use Filch's hands to find the next owner. Only the most adventurous students will appear in his office. We have set some restrictions for this."

Sirius fell into happy memories, his eyes narrowed, and he murmured softly.

After a while, he said with a gloomy expression: "It's a pity that the map is lost."

Felix pondered: "If I ask you to remake a Marauder's Map, can you do it? Lupin is also in school, he may be able to help."

"I know he is," Sirius said, he thought for a long time, "It will be difficult to remake it, I don't remember a lot of things..."

"We can try together, I am very interested in it."

"We?" Sirius looked at Felix blankly.

Felix did not answer. He looked at the time. "There are still two hours until ten o'clock. It's totally in time."

He said happily, "I plan to take you to Hogwarts. Of course, I have to contact Headmaster Dumbledore first. Well, we may also face inquiries from the Ministry of Magic. I will lie that I didn't catch you and let you run away. I don't know if anyone will believe it..."

Sirius stared at Felix. He felt that he was being severely ridiculed.

"Excuse me, where is the portrait of Phineas Black? I didn't see him in the row of portraits on the wall."

"...In the second bedroom on the right side of the second-floor platform."

Felix walked away. A few minutes later, he came back again. "It has been agreed that Dumbledore asked us to act secretly." He gently touched the ring on his left hand with his wand and took out a candy box with the words Honeydukes printed on it.

"What is this?"

"A Christmas gift from a little wizard. I haven't finished it yet and it's a bit greasy... But I thought I could use it to pretend to be a person."

"Did you cast an Untraceable Extension Charm?"

"Oh, no," Felix asked puzzledly, "Who would cast an Untraceable Extension Charm on a candy box?" He looked at the dazed Sirius and said, "I just happened to think of a suitable magic."

He pointed his wand at Sirius, and the tip of the wand burst out with a strong blue light.