This is part of an original serialized fiction project written and edited by the author. All story elements and characters are fictional.

The passageway leading to the hidden archive was now completely dark, the vibrations that had shaken the room still echoing faintly beneath their feet. Teodora, Leo, and Lucía were quickly ascending the spiral stairs, the key wrapped tightly in the old woman's hands.
"Do you think Méndez knows what we found?" Leo asked, his voice cracking from the effort of climbing.
"I'm not sure," Teodora replied, without turning around. "But if the system detected his intrusion, it's only a matter of time before he tries something more direct."
Lucía, right behind her brother, gritted her teeth.
"Direct? How direct?"
Teodora paused briefly as she reached the end of the passageway, looking at the siblings seriously.
"Méndez isn't working alone. If his team manages to figure out how to get here, they won't stop until they get what they're looking for."
Leo glanced toward the basement, making sure the entrance was still clear. "So, what do we do now? Do we just seal the entrance and wait?"
"No," Teodora replied, taking a thick marker out of her bag. "Let's make sure no one can get in."
She approached the edge of the passageway and began drawing symbols similar to those they had seen in the Echo Chamber, but with slight variations.
"What are you doing?" Lucía asked, observing the lines she was tracing.
"These symbols are protective seals," Teodora explained, continuing to draw. "My father taught me to use them in extreme cases. They function as a barrier that can't be easily breached, not even by someone with Méndez's technology."
"For how long?" Leo asked, worried.
Teodora finished the last symbol and stood up.
"I don't know. But it will be enough to give us an advantage."
Back in the lobby, the atmosphere was strangely quiet. The few neighbors passing by seemed oblivious to the events occurring deep within the building. Leo, Lucía, and Teodora paused by the reception desk, trying to plan their next steps.
"We can't stay here indefinitely," Lucía said, crossing her arms. "If Méndez knows something, it's a matter of time before he tries to break in."
Leo nodded.
"And with what we saw in that file... it's not just this building that's in danger."
Teodora looked at them, her face marked by concern, but also by a new determination.
"You're right. If there are other places like this, we must find a way to protect them as well. But first, we need answers."
Lucía raised an eyebrow.
"Answers? From whom?"
Teodora walked over to her father's journal, which she still carried. She opened it to a specific page where several names appeared in handwriting.
"This is a record of the original Keepers. Some of them left clues about their work, and others... might still be alive."
Leo looked up, surprised.
"You mean we could find one of them?"
Teodora nodded.
"It's a possibility. If anyone knows more about how to protect these secrets, it would be one of them."
"And do you know where to look?" Lucía asked.
Teodora pointed to one of the names on the list: "Álvaro C."
"This name appears in several meeting records. According to my father, he was one of the most active Keepers before the group disbanded."
Leo leaned forward to read the name.