Diluc got home frustrated and angry. He wouldn't listen to either Elzer or Adelinde. He had gone straight to his room and slammed the door. After two hours, he was calmer. He had taken off his jacket and opened the collar of the shirt that didn't allow him to breathe normally.

No matter how many times he thought about it, he still couldn't believe that the high command of the Order of Favonius would make that decision. Asking him to lie about who protected Mondstadt from the dragon Ursa was like asking him to dishonor his own father. He understood his reasons well, he knew that Mondstadt was vulnerable, and to say that Favonius had successfully faced a dragon would make the enemy think twice before attacking. Even so, it was an offense to his father, the true hero of that story, a man who had given his life to protect his son and Mondstadt when he didn't even belong to the Order.

Diluc was enraged when his commander, sitting in Varka's office while he replaced him during his absence, revealed that decision to him. Inspector Eroch, at his side, tried to make him understand the importance of hiding the truth. Diluc, who had been captain for four years and the favorite to become the future Grandmaster, found himself bound hand and foot. He could not defy his superiors, and neither his rank nor the truth could help him.

Finally, his pride didn't allow him to accept that. He would never deny his father the recognition for saving his people.

"You didn't even get there in time to see him die," he had told the commander and the inspector.

"Your father's wish was to protect Mondstadt," replied Eroch. "He would have agreed to this. It's the best for everyone."

"Don't you dare speak for him," Diluc spat. Then he took off his captain's cloak and left it on the table next to his vision. "I'm not going to be a part of this, and I won't keep fighting by your side either."

He heard footsteps on the other side of the door. Adelinde asked to enter and Diluc agreed.

"Sir, Jean has sent a message."

Diluc was surprised. He took the note handed to him by the maid and asked her to leave. He didn't reach for the letter opener or sit down to read it. He tore open the envelope and took out the paper.

"I just found out about what happened. I'm about to meet with Eroch to ask for explanations. I beg you not to be hasty. I'm sure we'll be able to find a solution. Just let me talk to Varka. I know he won't agree with any of this."

He looked at his friend's elegant signature before crumpling up the note and throwing it in the bin. He wondered if he could trust her. Those last few days had been one disappointment after another. First his father's death, then Kaeya's lies, and finally that. He covered his face with both hands and forced himself to think clearly. Jean would never betray him. He'd known her forever and he knew who she was. Then, Kaeya came to his mind. He also thought he knew him very well.

He decided to take a walk in the vineyard to clear his mind, he was going crazy. Before leaving, Adelinde told him that the meal would be served soon. Diluc just said he wasn't hungry.

He walked for a long time remembering the moments he spent right there with his father. Kaeya was always present. He still couldn't finish believing the truth. They had been so close for so many years, and his father had always trusted him. Then, Diluc remembered his father's last words before dying in his arms: "Diluc—, don't blame Kaeya for anything. You need each other. You must protect each other."

Until that moment, he had overlooked those words. Crepus always insisted on staying together and supporting each other, as if they were real brothers. Diluc assumed that this had been his last wish, but what if his father was hiding something from him? He wondered if he knew Kaeya's secret. If that was the case, why trust him? Of course, Kaeya didn't know, because he said that he had never been able to reveal his secret to his father.

Overwhelmed by the unanswered questions, he returned from his walk and headed towards the cellar of his house, arranged in the basement. He had searched through all his father's papers in the office and had found nothing of importance. But the office was not the only place where his father spent hours and hours. He also locked himself in the cellar, especially at night, when Kaeya and Diluc were already in bed. Convinced that he was hiding some secret there that would help answer his questions, he started looking around every corner.

The moon was already high in the starry sky when Elzer distracted him from his search.

"Sir, you should have something to eat and go to sleep," he told him. "I think you've lost track of time."

Diluc looked at him, exhausted. He had found absolutely nothing, but he needed to keep looking. There must have been something his father knew about Kaeya, some explanation that would help him forgive him. He felt so lonely without either of them. His father would never come back, but if he could get Kaeya back, if he could trust him again—. He collapsed into a chair and covered his face with his hands.

"Sir—" Elzer walked up to him and cleared his throat. Diluc looked into his eyes and noticed doubt in them.

"What's going on now, Elzer?" he said convinced that he was about to receive another piece of bad news.

Then Elzer took a key out of his pocket and handed it to him. Diluc took it, surprised.

"What does this key open?"

"What you're looking for."

Diluc looked at him puzzled. Elzer walked to one of the walls of the cellar, pushed aside a shelf, and tapped one of the bricks, which sank a little. A clicking sound was heard before the wall opened. The overture was the size of a door, and that was precisely what it concealed.

Diluc's eyes were going to pop out of their sockets. He had imagined a hiding place on the shelves, in the barrels or even in a bottle, but he didn't think about a secret door. He thought he knew his house perfectly, he had even seen the plans, and there was nothing according to them in that place.

Elzer encouraged him to open the door. Diluc came up and plunged the key into the lock. When the door opened, Diluc saw some stairs leading down to a second basement.

"What does this mean, Elzer?"

"His father asked me to show it to you if there was no other option left."

"What?"

"Come with me."

Elzer lit a torch and came down followed by Diluc. The stairs were narrow and made of stone. The musty smell was becoming more and more evident. Diluc was surprised when he arrived downstairs and saw that it was more than a basement, it was a catacombs. There were two passages blocked with stone. He wondered where they led and since when was that there, under the vineyard.

"In these books and notes you'll find everything you need to know: about this place, about the research of your father and about what murdered him."

"What?" Diluc got his heart turned over. "Are you saying that my father was murdered?"

"The dragon Ursa didn't attack your caravan by chance, that's for sure."

"What do you know?" asked Diluc. "What kind of research was my father conducting?"

"I don't know the details. Even he wasn't sure about anything, but I do know that he never backed down, not even when he decided to stop using his power."

"Are you talking about the power he used against Ursa?"

"That's right. About the power that killed him."

"So—I wasn't wrong—It wasn't the dragon," he said remembering his father in his arms. He didn't have any injuries, but he had aged for many years. The only explanation he found was that the dragon had cast a curse on him, but he had found no evidence that Ursa had such power.

"That gem you took from your father is the root of his power, and also the real reason for his death."

Diluc remembered the glove he had taken from his father when he died. That red stone had seemed strange to him, and he knew right away that was what he had used to face the dragon.

"Why are you telling me all this now?" he was surprised.

"I've already told you. Your father asked me to do it if there was no other option."

"What does that mean?"

"Mondstadt is in more danger than you think," Elzer assured. "Varka tried to keep Crepus away from all this, but your father never left, even after the deal he made with him after Kaeya's appearance."

"What does Kaeya have to do with all this?"

"Varka didn't trust him. Your father promised him that he wouldn't use his power again if he let the boy stay in this house."

"Why has my dad always trusted Kaeya?"

"After a while, he discovered his provenance. Still, he never doubted him. He loved him like a son and was convinced that both of you would be the salvation of Mondstadt."

"The salvation of—? Why?! I don't understand anything, Elzer."

"I hope you can find that answer here," he pointed to some shelves full of books and scrolls. "I'm sorry I can't be of more help, but your father didn't tell me everything. It will be an honor to serve you as I served him, if you wish."

Elzer withdrew, leaving Diluc with more doubts than he had minutes before.

He began to glance through scrolls and pulled books off the shelves trying to figure out where to start. He had no idea what he was looking for, so he didn't know where to focus. However, Kaeya kept coming to his mind, and according to Elzer, his father was convinced that both of them would be the salvation of Mondstadt, so he decided to start with Kaenri'ah. He searched for all the information about the history of that nation and began to investigate.

That night, he was unable to sleep and he discovered many things that he had never heard of. If he had doubted the gods when they granted a vision to Kaeya, now there was no doubt in his mind that he could no longer trust them.