As the rocky trail twisted a serpentine path ahead of Rey and Luke, it curled around the mountain and promptly stopped at the mouth of a large cave. Rey instantly halted in place as she remembered her last visit to a cave on the island. The shiver that went up her spine had nothing to do with the cold morning breeze and everything to do with the dark version of herself she'd faced.

"Worried?" Luke questioned without turning around.

"Just remembering," Rey explained.

Luke paused in front of the cave and turned toward her.

"Remember specifics," Luke instructed. "How did the dark side cave feel before you entered it? Do you sense that here?"

Rey closed her eyes and concentrated. The previous cave had a coldness to it, and the darkness itself was a physical presence when she'd walked its foreboding passages. She couldn't sense any of it here, but something else registered, a brief wisp of something she couldn't quite identify. Her brow furrowed as she reached out a hand to touch the sensation in the Force, but it moved away as if she were trying to capture a handful of mist.

"I don't know," Rey admitted as she lowered her hand and opened her eyes. "There's something in there, but it's different from the other cave. I can't be more specific."

"I'm impressed you sensed it at all," Luke praised. He gestured for her to follow as he took the lead into the cave.

The passageways were dark and the cold wind from outside howled in after them. Rey squinted her eyes, but she could barely see Luke a few steps in front of her.

"Having trouble?" Luke questioned as he paused and glanced over his shoulder. Rey skidded to a stop to avoid running into him. "Remember, the Force is everywhere. Its energy surrounds us and fills this tunnel. Close your eyes and see with the Force."

"I..," Rey began, but the dark silhouette of Luke held up a hand to forestall any objections.

"Trust me," he told her.

Rey closed her eyes and reached out with her mind to the Force. As she focused, the cavern passage lightened as if illuminated by a pale mist. The walls were still dark, but the open spaces were brighter gray. When she looked toward Luke, she beheld a supernova of white light, and her concentration slipped. The tunnel plunged back into darkness. Rey sighed as she began again.

It took a few minutes before she was able to get her Force vision to work again as her frustration was hampering her efforts. When the tunnel appeared in its gray mist of illuminated energy, Rey was careful not to look toward Luke and the blinding concentration of power within him.

"You take the lead," Luke suggested. "I'll tell you where to go at any junctions."

Rey nodded and started down the passage. She kept her eyes closed and found her way through the Force. Several times the tunnel split, and Luke would say either right or left to direct her accordingly. The odd sensation Rey had detected outside the cave came again, and she got a better hold of it this time. The feeling was warm, like the smile of an old friend, but it remained elusive as if she couldn't recognize the face of the friend. Because she'd never felt anything like it before, she'd no idea what it could be, but it was getting stronger.

"Your pace is slowing," Luke pointed out.

"Oh, sorry," Rey apologized.

"What is it?" Luke questioned.

"I sense something," she admitted while continuing forward. "It's growing stronger the further down we go, but I can't figure out what it is."

"Hold a moment," Luke instructed, and Rey paused with him in the lightless corridor of stone. Luke placed a hand on her shoulder and it was as if she'd been nearly blind and given an optical enhancement lens. The weak sensation she'd been feeling became perfectly clear, and she could detect everything.

"They're alive!" she blurted loud enough for it to echo off the close walls. "Your entire Jedi Academy is here!"

"Yes," Luke confirmed. His assisting of her Force vision provided the control she need to not only sense what lay beyond the rocks ahead of them but to adjust to various intensities and keep from being blinded by his presence. Luke moved around in front of her to face her directly. "The Dark side presence here is so intense, it can mask them from detection, keeping them safe from the First Order. Now you know why I came to this place, and why I couldn't return to the Republic."

"Of course," Rey said as the realization formed her in mind.

"When I was training Ben Solo, before he became Kylo Ren, I sensed a growing darkness," Luke went on. "I couldn't tell if it was from him or something trying to get a hold on him. As a precaution, I moved the rest of the students here for safety before going back to Ben for more intensive training."

"If you had eliminated him, you could've save a lot of lives," Rey pointed out.

"He's my nephew," Luke reminded. "Besides, I only sensed a darkness about him. He hadn't done anything. There was good in him then, and even now I know it's still there. I hope I can help him before this is done."

"I overheard Han tell Leia that Kylo accused you of trying to murder him," Rey informed him.

"So, that was the lie used," Luke replied with a humorless smile behind his beard.

"Neither Han nor Leia believed it," Rey went on.

"Giving up on my family isn't something I do," Luke told her. "After moving the students, I came back to find the Academy a burning ruin. There was no sign of Ben. Whatever darkness I'd sensed had him then, and I could only protect what remained. I left my R2 unit behind with a piece of the map to find me, and I went to give the other half to a friend for safe keeping."

"Now Ben Solo is Kylo Ren," Rey finished the story, "the First Order's own private monster."

"One of my greatest regrets is I wasn't able to save Ben before it came to this, but it's not over yet." Luke responded.

Helping Rey maintain her focus through the Force, Luke waved a hand to move a boulder aside and open the way into a vast underground chamber. Rey breathed in sharply in surprise as she beheld extensive training grounds and more than two dozen students with lightsabers going through their paces. The room echoed with the hum of blades and the clash of opposing energy fields.

"Your basic training is over," Luke said, lowering his hand from her shoulder. "Now, your real training begins."