Inside the cave.

The two people looked at each other in silence.

"The note has been there for a long time." Harry waved his wand and picked it out. "It's not recent."

"It seems that I was wrong. The traces from more than ten years ago were not from Voldemort coming to check whether the Horcruxes were stored safely, but from this unknown gentleman."

His eyes rested on the three letters "RAB".

"It seems that he is not a member of the Order of the Phoenix." Harry analyzed, "You don't know this, otherwise you would be so stupid to go all the way back."

"I just don't want the Horcrux to be destroyed." Dumbledore shook his head. "If I had known earlier, I would have noticed the abnormality in your body."

"An unsung hero who fought against Voldemort."

"RAB"

He repeated the abbreviation.

"Let's go out first and find a warm place." Harry stuffed the note back, "and then think about who it could be."

At this point, he paused for a moment and said, "Now you don't have to worry about anything."

Dumbledore smiled and nodded: "Of course."

Voldemort signed a contract with this reef and this piece of nature. Of course, he was not without a solution, but before he got the Horcrux, he did not dare to destroy this place. Who knows what magic would be used to deal with this matter? Now there are still traces to find the Horcrux, but if it is teleported away, it will be a very headache and time-consuming task for Dumbledore.

The Horcrux isn't here now.

Dumbledore no longer had any concerns. He raised his wand high and pointed it at the dome on the island in the middle of the lake.

The darkness surged and the lake rippled.

The contract forced the reef to resist the greatest white wizard, but it was just an old spell and was powerless to resist.

With a loud bang, a fresh sea breeze blew in, and raindrops came crashing down, hitting the surface of the Black Lake, making a sharp, wailing sound.

Dumbledore muttered, "Oh, yes, and this thing."

He turned his wand and pointed it at the Black Lake.

Harry glanced sideways.

Vanishing spell.

But Dumbledore's vanishing spell was not aimed at the lake, but at the concept of "contract" itself.

With a slight wave, the dark and tiny breath completely disappeared.

The black lake water was boiling and surging more violently, the earth was shaking, the black marble slabs were crumbling and about to sink, and with a rumbling sound, the cracks in the reef dome were expanding. It was not the influence of magic, but without the maintenance of magic, its fragile structure could no longer maintain its existence and was collapsing bit by bit.

"Let's go." Dumbledore stepped forward and took a step into the void.

Rocks collided and flew over, forming stone steps under his feet. Harry followed him, and the two of them quickly walked out of the reef.

Standing at the end of the stone steps, watching the reef under your feet slowly sink into the sea.

With a gurgling sound, a large piece of white foam emerged and a small whirlpool formed, stirring up the sea surface.

"Another memory of Tom is gone," Dumbledore muttered quietly, grabbing Harry's sleeve.

Apparition.

With a snap——

They twisted their bodies and appeared outside the Three Broomsticks Door in Hogsmeade in the blink of an eye.

It hasn't rained here yet.

But the air is filled with suppressed moisture, and it won’t be long before it becomes like the seaside.

They pushed the door open and walked in.

It's not the weekend, so there are not many students dating in the bar. Most of the customers are residents of Hogsmeade or strangers who come here to travel or visit relatives.

"A glass of honey water, Harry, would you like some whiskey?" Dumbledore greeted Madam Rosmerta.

Harry waved his hand: "A glass of whiskey."

Wait for the drinks to be served.

"Harry, who do you think RAB will be?" Dumbledore took a sip of honey water.

Harry was silent for a long time, waiting for the table to be finished. He glanced at Ms. Rosmerta, who was walking away knowingly. "Let's think about it. First, rule out the possibility that he is a member of the Order of the Phoenix. Otherwise, he would definitely tell you about this."

Dumbledore nodded.

He has such faith in the Order of the Phoenix and in himself.

The most important thing is that in the Order of the Phoenix, there is no one with the name or nickname abbreviated as "RAB". Although he is very old, his memory is not as confused as that of ordinary elderly people.

"If it's not the Order of the Phoenix, then it can't be someone who is against him." Harry continued to tap the table. "With Tom's character, it's impossible for him to keep someone who can cause him great trouble, unless he has the protection of someone he can't deal with. But besides you, are there other wizards like this?"

Dumbledore shook his head.

Harry paused and looked at the "note" on the table: "That thing is Tom's biggest secret."

"It is very likely that those who knew he had this thing were told by him."

"A 'friend' who had searched for Horcruxes with him, or someone he trusted extremely, at least like Malfoy and Lestrange, who gave him the things for safekeeping."

"Or let him guard it. Even though the cave is well-arranged, what's the problem with a little more precaution?"

Dumbledore thought of something.

Harry called for Madam Rosmerta to refill his glass.

After she left, he continued, "Let's think about the handwriting on the note. It was sloppy, even a little ugly. Although it was written in a hurry, even if he wrote it carefully, I'm afraid he wouldn't write it very well."

"A young man."

"Young people with average abilities, talents, and personalities."

Dumbledore shook his head, "Harry, that's not a young man of average character to have the guts to stand up to Tom."

"I mean the way he behaves on a daily basis," Harry added with the qualification, "a young man like that can't possibly be Tom's friend."

"So……"

"Most likely the same as Malfoy and Lestrange."

Having said that, Harry drank the full glass of wine in one gulp.

"A person or family that Voldemort trusts to keep the thing for him."

"Not very old."

"The last name begins with the letter 'B'."

"The Noblest and Most Ancient Pureblood Family, Black."

Dumbledore nodded.

Harry went on: "Sirius starts with S, SOB"

"I don't know if you, Professor Dumbledore, have ever paid attention to the Black family tree. Sirius has a younger brother, and Kreacher occasionally mentions him."

"Regulus Arcturus Black."

"RAB"

Dumbledore couldn't help but applaud: "What a clever deduction."

Harry tapped his cup. "What's even more gratifying is that we may find clues to where Tom hid his Horcruxes."

"He might consider bestowing the Horcrux on his servants and letting them keep it. Malfoy, Lestrange, Black, or any other family?"

"First, we exclude purebloods like Crouch, where only one person stands on the side, not the entire family."

Dumbledore said skillfully, almost without any thought: "Avery, Carrow, Nott, Rosier, Rowle, Selwyn, Travers."

Harry blinked. "So many?"

"More than one-third of the Death Eaters agree with Tom's point of view." Dumbledore nodded. "Of course, some of these families may not support him so firmly, but to be honest, they can provide a lot of help for Tom's rise."

"Obviously there aren't that many. Maybe the rest are in their hands. Maybe there are only one or two? But it's better than having no idea." Harry let out a long breath, "Professor Dumbledore, you should be thankful for one thing."

"I've never done a good job collecting debts before."

Dumbledore raised an eyebrow. "You mean Potter's shampoo?"

“I am also a loyal user.”

Harry took out his wand, conjured his Patronus, gave it a few words, and watched it fly in the direction of Hogwarts.

"I asked Sirius to wait for us at home. Shall we set off now?" As he spoke, he took out a Galleon and threw it on the table.

Dumbledore sipped his drink. "Let me finish this one."

Under Harry's fixed gaze, he couldn't help but speed up, walked out of the tavern in a panic, and Apparated away with Harry.

In the Blake mansion.

Kreacher, who was enjoying the rare empty and clean Black house, couldn't help cursing in a low voice when he saw three people walking in in two groups, one after the other.

Sirius was confused: "Harry, Professor Dumbledore, can't we talk about it at Hogwarts? Why do we have to come to my house?"

"We may have discovered something that may be related to your brother." Dumbledore beckoned him to sit down.

younger brother?

This word is too unfamiliar.

So much so that his first reaction was that he couldn't even think of Regulus: "James? Or Remus?"

"It's Regulus." Harry forced open his memory.

This familiar yet unfamiliar name.

"Ah, that idiot?" Sirius looked indifferent, "What happened to him? Did you find something about him?"

"I don't want to paint him..."

Kreacher came over and cursed: "Ah, this stupid heir of the Black family, now he starts to say such things again, how can he slander the true heir of the Black family like this..."

"Kreacher, shut up." Sirius interrupted, gritting his teeth.

Harry sat down opposite Sirius: "My dear godfather, I support Kreacher's words this time."

Sirius was startled.

Dumbledore nodded: "Even I have to admit that Regulus is a great hero and a true warrior."

"The Sorting Hat always says that there are no two people in the world who are more alike than Gryffindor and Slytherin."

"Yes, its words are always right."

"There is great courage in Slytherins, too."

Kreacher stared blankly at Harry and Dumbledore, somewhat at a loss, and rubbed his hands together into a ball.

"Warrior? Regulus?" Sirius was confused.

In memory.

The image of a weak and cowardly child who allowed himself to be manipulated by his family emerged.

In his appearance, which was similar to his own, there was only childish ambition and childish corruption.

It can hardly be associated with the word "warrior".