The Resistance sees them off at dawn, and only the strict timetable they're on — that all of them are on — keeps Finn from hugging his friends and his family goodbye any longer. Poe, Rose, Slip, Zeroes, Karé, Pava, and Paige are all going off to the Messenger and the Outer Rims, and the rest of Black Squadron (led by Snap) will lead the New Republic's armies to wrest the planets back from First Order control. His mother and Ffion and Jannah and Lando will be off to liberate Artorias as soon as Finn leaves. There's a very real chance that he might not ever see the people he cares about again, and that knowledge makes him tighten his embrace until Luke gently reminds him that they need to get going.

Since Lando is piloting the Millennium Falcon for the mission to Artorias, Finn and Rey and Luke have to make do with a smaller ship. Lucky for them, it only takes two jumps through hyperspace before they arrive at their destination, and Luke puts the ship on autopilot for the landing so he can unfurl a map of the Crystal Caves on the dashboard.

"The Empire nearly drained Ilum dry when they were building the Death Stars," Luke says gravely. "And the First Order came even closer, when they built Starkiller Base. But the Force provides, just as it did for me and all the Jedi before. The kyber crystals have learned to hide themselves from those who they think are unworthy."

Rey bites her lip. "How do we know that we are?" she says. "Worthy, I mean."

Luke puts his hand on hers. "The crystals know," he says. "A crystal is formed whenever the Force awakens in a person with a strong heart. A worthy person. To prove your worth, you have to overcome whatever challenges the Force throws at you in there. It'll play tricks on you, on your mind, and use your weaknesses against you."

Great, Finn thinks. No pressure.

Luke's expression softens at the poorly-concealed panic on both Finn and Rey's faces. "I remember going through this myself, you know," he says. "I'd just found out Darth Vader was my father, and Han…he'd been sealed in carbonite and stolen away. I didn't know if I was worthy either. But I tried my best, and the crystal found me." His eyes meet theirs. "No student I've taken here has a stronger heart than either of you. You'll get through this. I promise."

Rey's gotten used to a lot of things since leaving Jakku. Grass. Readily available water. Cold breezes. Food that doesn't come in portions that taste like sand. People who care about her. The idea that she actually matters. Cold, on the other hand, real biting cold that forces her to shove her hands in her coat pockets and makes her breath turn to white mist — well, getting used to that will take some more time.

She's got her new lightsaber handle holstered at her side, and her staff strapped to her back. Her movements feel clunky and stiff thanks to the bulky coat she's bundled up in, but her boots are sturdy and her pace is steady, and Finn's hand is in hers, and Luke is behind them both, and that's all enough to keep her heart steady too. It'll be alright. Luke managed to pass this test, and she can too.

After walking in near silence for what feels like hours, admiring the gleam of icy crystals embedded in the walls and near frozen pools of water in the cracked ground, the three of them come to a fork in the road — one path leading to the left, and the other curving off to the right. Rey looks back at Luke, nervous, but Luke just nods. It's clear, then. She'll have to do this on her own.

"You've got this," Finn says. He squeezes her hand as he turns to face her, and she squeezes his hand back. Hopes with everything in her that she doesn't look as terrified as she feels. "See you back here when it's all over."

Rey leans up and kisses Finn, praying that that'll be true. "See you then."

The left path leads into darkness that engulfs her completely. Rey blinks furiously, waiting for her eyes to adjust, and grips her lightsaber handle tightly in lieu of Finn's hand. She'd spent years alone on Jakku scavenging in caves much darker than this one — she can handle this. She can handle anything.

Almost as soon as the thought forms, tiny pinpricks of light begin to glow around her, easing the darkness away. There's hundreds of them — thousands, maybe, glowing as bright as the suns — and Rey turns, trying to take in as many as she can. "Which one of you is mine?"

Rey reaches towards the one closest to her, but it zaps her hand like a bolt of lightning and she immediately snatches it back, swearing. Instead of fading away, it glows brighter until she has to turn away from it completely, and so does the next one that Rey reaches for, and the next one. Her eyes are squeezed so tightly that her entire face aches from the strain, but she can still feel the light digging into her, trying to blind her.

The kyber crystals have learned to hide themselves from those who they think are unworthy, Luke had said. Rey moans, nauseous from the overwhelming brightness, and the crystals seem to echo the sound. Of course she's unworthy. She always has been. She's not a hero like Finn or Luke, she's…

No. Rey bites down hard on her bottom lip, and the pain helps her concentrate. She'd fallen to her knees, and rises again through gritted teeth. "No," she says, out loud this time. "You won't make me think that. I know what I am. I know who I am."

The brightness seems to recede from behind her lids. Begging the question, Do you?

"I'm Rey," she says. "I'm a Jedi. I'm one with the Force, and the Force will guide me."

Slowly, the brightness recedes. Rey opens her eyes — and sees an older woman standing before her. She's clad in a simple brown cloak and dark pants tucked into worn boots. Her reddish-auburn hair falls in loose waves around her shoulders, and she has a sharp chin and even sharper hazel eyes. Her stare is appraising, even as her form flickers. Looking at her, taking her in, Rey forgets how to breathe.

"Mama?"

Mara Jade Skywalker smiles. Her eyes are bright with tears. "Hello, Rey."

"Are you…" Rey reaches for her, but hesitates when Mara's form flickers again. "Are you real?"

"What do you think?"

"I…I'm not sure."

Mara inclines her head, smiling slightly. "Good. Never let down your guard."

Rey squeezes her eyes shut, wondering if the light had blinded her into seeing the impossible. But when she opens her eyes again, Mara is still there, still whole and well (if not alive). Rey's heart aches at the sight of her. I wish you were real.

"I'm so proud of you, Rey." Mara's eyes, so like Rey's, search Rey's face hungrily, as though she'll never be able to look at Rey enough. A lump rises in Rey's throat as her mother draws closer. "Look at you. You've come so far. You inherited my stubbornness in spades. Maybe even some of your father's."

Rey's laugh is watery. "It's a good combination."

"You bet your boots it is," Mara says, with a tearful laugh of her own. She moves to take Rey's hands in hers, but her own hands begin to evaporate like cold mist the closer they come to Rey's. Rey pretends not to notice. "I've come to warn you, Rey. The way I wish your father and I could have warned your cousin, had we known what was ahead."

Rey's muscles tense in anticipation of a fight — or maybe just from the mention of Kylo Ren. If she still isn't completely ready to call Luke her father, she's eons and galaxies away from acknowledging Kylo Ren as her cousin. "Warn me about what?"

"I knew the Dark and the Light Sides of the Force like the back of my hand," Mara says, her voice grave. "I was…intimately acquainted with them, in a way even your father never was. But he knows — and I knew — that peace can only come if the Force is balanced. Equally Dark, equally Light. Even after the First Order rose, even after your father disconnected himself from the Force and Snoke grew more powerful, the Force was able to keep its balance. But Snoke's death and Kylo Ren's ascension to Supreme Leader have stretched the balance of the Force thinner than ever. Can you feel it?"

Rey closes her eyes, and reaches out. She can feel the cold of the darkness and the strange warmth of the light as always, but it feels…stranger, now. Harsher, more bitter. The balance, the connection between the two has begun to fray and wither from the power of the Dark Side that Kylo Ren wields, the amount of Darkness that Snoke had poured into the Force when he'd died. "Yes," she whispers.

"Your father and I struggled with the Dark and Light in us all our lives," Mara says. "I know that you've struggled with it too — that the Darkness whispers to you now and again, trying to tempt you. And you've been so strong, so wonderfully brave and stubbornly strong, but you need to keep fighting, Rey. Kylo Ren wants nothing more than to tempt you to the Dark Side — if you or Finn succumb, all is lost. The Force will never be at peace again. The Dark Side will win. And you can't let that happen."

Rey's gaze circles the cave, as though the physical manifestation of the Dark Side of the Force will pop out at any moment and attack. "I won't surrender to the Dark Side," she says at last, meaning every word. "I won't let it or Kylo Ren win. I promise."

In answer, Mara reaches into her pocket, pulling out something surprisingly solid — a magenta kyber crystal. "Take this," she says. Her ghostly form makes the crystal glow eerily in the dim light. "It's what you came for, isn't it?"

Rey reaches for it, but stops just as her fingers brush against the smooth facets. It feels just like touching any other rock — the pull that Luke had described isn't there. "Thank you," she says, and means it. "But I think I'll find my own."

Mara grins. "Good girl," she praises. The crystal between her fingers disappears. The rest of her begins to fade away too — just as a green crystal embedded in the rocky cave wall behind her begins to glow. Rey takes a step forward, as if yanked by an invisible rope connected to her navel. Mara's voice grows thinner, airier, until all that is left of her is an echo. "I love you, Rey. Take your final steps. I know you'll do what's right."

Rey uses her knife to chip the whole crystal out of the wall, and blinks back tears when it's in the palm of her hand. It feels like holding her fingertips to someone's pulse; like it's a living, breathing thing, in perfect sync with her own heartbeat. She'd found it all on her own. She really is worthy.

I'm a Jedi, she thinks. Like my family before me.

Between the kyber crystal strobe light show and the path through the cave that's taken him through a whole lot of nothing, Finn is beyond ready to get the hell off of Ilum as fast as physically possible. Only the faint flickering of the gem-lined pathway keeps him going forward.

Finally, he comes to a dead end, and the crystals stop glowing — all except two, embedded in the main wall an equal distance apart from one another. Both the same size, and shape, and brightness. Finn sizes both of them up, worrying at his bottom lip with his teeth. What if it's a trap?

"Trust your instincts, Finn Solbourne."

Quick as a flash, Finn whirls around, unholsters his blaster and aims it at the man who'd spoken. He's old and white-haired, but carries himself like he's anything but frail. He wears a deep brown cloak over a belted white tunic and brown boots, and stares at Finn with what the Troopers used to call old soul eyes, the kind of gaze that had seen a thousand harsh battles and few victories. Finn swears he's never seen the man before, but something about him is familiar enough that he lowers his blaster. "Who are you?"

The man smiles, but strangely — like he'd gone without the action for so long he'd forgotten how to. "My name is Obi-Wan Kenobi."

Finn's breath catches. "The Obi-Wan Kenobi? Luke's teacher?"

A nod. "And his father's teacher as well."

"I…" Shit. Finn shakes his head in wonder, and holsters his blaster. "What are you doing here?"

"A great battle lies before you," Obi-Wan says, his voice grave. The crystals glow around the two of them like embers in a dying fire. "You must be fully prepared and at one with yourself before you can battle my namesake and win."

"Your — oh. Right." Finn wonders how Obi-Wan had felt to learn that Han and Leia named their son after his alias. How Obi-Wan had felt watching his namesake grow up to be a monster. Then the rest of Obi-Wan's words slide home. "What do you mean, fully prepared?"

"You aren't letting your instincts guide you," Obi-Wan says. "Not fully. In order to survive, you must place your trust in the Force, not just your capabilities or Rey's capabilities. Let go of your conscious self and act on instinct."

Easier said than done, Finn thinks, but he can't help but feel that Obi-Wan is right. Trusting himself or Rey or Luke is one thing, but placing every grain of his trust in something that he can't even see is a far more difficult thing. Kylo Ren has given all of himself to the Force, and it's only made him more powerful. If Finn does this — if he and Rey do this — they'll be on equal ground again. "How do I do that?"

Obi-Wan spreads his hands in answer. "You're a Jedi," he says simply. "The answers are around you. Reach out."

Finn bites back another sarcastic comment and does as told. He closes his eyes, and reaches out, feeling the Force crackling at his fingertips. The Light and the Dark, warring for his attention, and he shoves the coldness of the Dark Side away as easily as shooing a fly. It's familiar — six months of Jedi training have made him well acquainted with the Force. But it's like he's standing at the edge of a pier, waiting to jump into a pool of water so deep he can't even see the bottom. Something is stopping him, like a rope is tied around his waist.

"You won't lose yourself," Obi-Wan says, from far away. "Let go."

Finn takes a deep breath, and then takes the plunge.

Every sense is immediately heightened and dulled, brightened then darkened. He feels like he's in a swirling kaleidoscope, on fire and frozen all at once. He can feel everything around him — Obi-Wan's strange barely-there presence, the humming of the crystals, even the exact places where Luke and Rey stand, in separate caves, on separate journeys. He can feel the Force eating away at his bones, his heart, the breath in his lungs, and makes an effort to pull back, to gain control over the warring sensations. Somehow, he manages it.

"Very good, Finn," Obi-Wan says. "You have the control of a true Jedi."

Finn does not answer. He's too focused on the crystals in the cave wall, both gleaming brighter than ever. Through the Force, can sense the coldness coming from the one on the left — senses the trap that will ensue if he tries to chip it out of the wall — and pulls out his knife, cutting the right crystal free. It glows and thrums in his hand like a human heart, which is both parts unnerving and too cool for words.

"Do not be afraid to let the Force guide you, Finn Solbourne," Obi-Wan says. He's fading away now as quickly as he'd appeared, but the smile on his face is satisfied. Proud, even. "Let the Force guide you to victory."

I'll settle for the Force guiding me the hell out of here first, Finn thinks. No sooner does the thought materialize than do the crystals embedded in the cave floor begin to glow again, forming a path to freedom. He turns to thank Obi-Wan for the help, but the ghost is gone already.

Luke and Rey are waiting for Finn in the same place he'd left them, and an equally proud smile crosses Luke's face when he sees the white kyber crystal in Finn's hand. "Well done," he says, and claps Finn on the shoulder. Finn nudges Rey's shoulder and grins at the green kyber crystal cupped between her hands. "Both of you, well done. I knew you could do it. Come on, let's get these crafted before we get back to the ship."

They sit on the cave floor in a circle, their knees almost touching. A cold breeze stirs through the cavern, making Finn shiver. Or maybe it's just the low hum of the kyber crystal in his hand.

"Do you have your saber parts?"

Finn and Rey nod.

"Place them on the ground before you."

Rey and Finn unholster their saber handles and place them gently on the ground in front of them. Finn's is a medium-sized metal cylinder like Luke's, made from an Artorian titanium alloy with a simple grip; Rey's is barely two hands' lengths long, made from a chunk of metal that had been torn from the Millennium Falcon. If the crafting works, it'll look just like her staff, the weapon Finn knows she still feels the most comfortable with. A shiver of excitement, not cold, goes through him now.

"Hold your crystals out in your dominant hand," Luke says, "and close your eyes. Picture the lightsaber that will make you strong in battle and humble in retreat. Picture the pieces coming together as one. Forge your handle and the crystal together with the Force."

Finn concentrates. He imagines wielding a lightsaber in battle that will help him defeat Kylo Ren, protect those he loves, keep himself safe. A lightsaber that Kylo Ren won't be able to use against him, that will fit in his hand better than even a blaster could. And, slowly but surely, he can feel the Force buzzing at his fingertips, lifting the white kyber crystal into the air — he doesn't dare open his eyes, but he doesn't need to. Somehow, clear as day, he can sense the parts joining together, molded together by the Force. The Force that he'd wielded.

When he opens his eyes, his lightsaber is floating in front of him — and Rey's is floating before her too. At Luke's nod, Finn reaches for it, and Rey does the same. The moment his fingers wrap around the hilt, he almost drops it on the ground; the metal is hot, so hot it almost burns him, but he grits his teeth and sticks it out until the burning fades into a light warmth. He squeezes the grip that he'd crafted and feels a strange hum of pressure in return, like the hand of an old friend.

Rey's smiling from ear to ear. "Can we try them?"

Luke spreads his hands. "Be my guest."

Rey jumps to her feet, and Finn and Luke give her some space. Carefully, she ignites her lightsaber — and a solid beam of green light emerges from the top and the bottom ends. She'd created a double-edged saber, just like she'd wanted to. Finn's grinning so hard it almost hurts, and stands up to try his out for size. A white beam of light snaps out of the top, and he twirls the saber for practice (once Rey and Luke move back a little).

"We did it," Rey tells him, extinguishing her blade, and Finn bumps her shoulder after doing the same.

"Hell yeah we did."

Luke wipes his eyes. "I'm so proud of you both," he says, his voice a low rasp, full of emotion. He clears his throat and tries again, standing as he does so. "You're going to be great Jedi. You already are. And…it's because you're already such great Jedi, whom I trust profoundly, that I want to ask if you'll help me with my plans after this infernal war ends."

Finn frowns. "Your plans?"

Luke nods. "Once Kylo Ren and the First Order are defeated," he says, "I plan on traveling the galaxy far and wide to search for more Jedi. We are not the last of our kind. I can sense it."

Rey's eyes are nearly as bright as her smile. "Does this mean you're going to try again?"

"I am," Luke says, firm. "The Dark Side tried to break me before, but I won't let it get the better of me again. I'll not abandon the next generation of the Light again."

"How touching."

Finn's heart shoots up into his throat.

Kylo Ren stands before them, smiling, lightsaber in hand. "Hello, Uncle," he says. His eyes gleam yellow; his pale face is waxen and grotesque, still scarred from his battle with Rey. Hanging from his belt is a bag humming and glowing with kyber crystals. "Long time no see."

"Hello, Kylo Ren."

A flicker of surprise. "What? No pleas for me to renounce my name? No desperate desire to find the good in me?"

"I know when the good inside someone has long since fled," Luke says. His lightsaber is at the ready; next to Finn, Rey is trembling with tension, eager to strike. There's so little room in the cave that one wrong move will lead to decapitation. "And you haven't been Ben to me in a long, long time."

"Have I not?" Kylo Ren's eyebrows arch. "How interesting. Your lovely wife thought of me as Ben up to the moment my master shot her ship out of the sky. On my intel."

Luke stills. "What."

"Well now, Uncle." Kylo Ren's smile is so cruel it sends shivers down Finn's spine. "You didn't think she told no one where she was going, did you?"

Luke pounces — that's the only word for it that Finn can think of that fits the animalistic roar of rage that tears out of Luke's throat. A darkness thicker than blood that suddenly envelopes the cave, broken only by the slice of Luke and Kylo Ren's lightsabers: fiery red and the bright green of life.

HOW DARE YOU, HOW DARE YOU echoes across the cave in jagged, imperfect lines, in perfect tune with Kylo Ren's laughter. Finn doesn't even have to look at Rey before he takes off at a sprint after Luke, knowing she's running beside him. The cave narrows and widens like a meandering stream, and Finn ignites his lightsaber as a torch — only to see that the crystals embedded in the walls have begun to bleed from the power of the Dark Side.

They come to a halt in the same fork in the road that they'd passed on the way in — one path leading back to the entrance, where their ship is, and the other… shit.

Rey realizes at the same time he does; her face drains of color in the light provided by Finn's lightsaber. "He's trying to draw Luke into an ambush."

"Luke! Luke, come back!"

Much anger in him, like his father, Yoda had once said, when Luke had been too frustrated by his soon-to-be master's antics to see straight. The words had come back to him often over the years — after Darth Vader's revelation, after Palpatine's struggle to persuade Luke to the Dark Side, now that the truth of his nephew's involvement in Mara's death has finally been spoken. When fury had driven every thought from his mind, leaving nothing but an instinct to follow. An instinct that often led him into trouble.

Trouble exactly like the fight he'd found himself in now.

"Luke! Luke, come back!" Kylo Ren imitates Finn's distant shout in a mocking, patronizing voice as he swings his lightsaber at Luke with a vengeance, driving him deeper into the Crystal Caves. The crystals hum and shriek as Kylo Ren nears them, blood dripping from their facets. "How the mighty have fallen, Uncle. Having to resort to teaching a scavenger and a Stormtrooper the ways of the Force."

"You know just as well as I that they're strong in the Force." Luke dodges Kylo Ren's attacks and brings his own lightsaber down — missing at the last moment and reducing a row of crystals to ash. He ducks into another cavern, hiding from Kylo Ren with bated breath. "Stronger than you ever were."

Luke can hear Kylo Ren grinding his teeth as he stalks into the cavern. "You and I have a very different definition of what makes someone strong in the Force."

"You've got that right, kid."

Luke jumps out from behind a crystal-studded boulder and feints just in time, blocking Kylo Ren's parry — lunging forward as Kylo Ren leaps back, beating him back toward the cave wall. He brings the blade of his saber down on the hilt on Kylo Ren's saber hard, knocking it out of his hand and sending it flying across the cave. Only Luke's instincts keep him from getting decapitated as the lightsaber makes a U-turn on the cave floor and returns to Kylo Ren's hand, letting his nephew rejoin the fight with a renewed ferocity.

"You could have been better than Grandfather ever was," Kylo Ren snarls. He's got Luke on the defensive now, forcing him back. "The power of the Dark Side was yours for the taking and you squandered it!"

"You always seem to forget," Luke ducks, twirls away from the blade that singes the hem of his tunic sleeve, "that my father turned away from the Dark Side, as did I."

"And I," Kylo Ren growls, "never will."

Kylo Ren dodges Luke's strike and kicks Luke in the stomach, and Luke is the one sent flying this time, slamming his head against the cave wall with enough force that his knees collapse and his vision blurs from the pain. His lightsaber has spun out of his hand, but he can't sense it anywhere near him. The Darkness is too strong.

"You could have been a great ally in my new world," Kylo Ren says. "But it seems you insist on being the same nuisance you always were. Goodbye, Uncle."

"NO!"

A jagged spire of rock the size of a quad-jumper spurts from the ground and knocks Kylo Ren off his feet and through the rocky walls, knocking the lightsaber out of his hand as well. Luke is yanked to his feet by a familiar pair of hands, forced to move — Finn presses the lightsaber back into his hands as the three of them run out of the cave, Rey leading the way back. Did Rey do that, or had it been both of them? Either way, Luke is thoroughly impressed (and even more thoroughly relieved).

They've just tasted fresh air and felt the bitter cold wind on their faces once more when Kylo Ren's bellow of rage echoes out of the cave. Luke can see him as a tiny pinpoint in the distance, waving his lightsaber as he hurtles toward the entrance. The shrieks of the kyber crystals reach maximum volume.

Finn thinks faster than any of them. With a sweep of his hands, the rocks around the cave's entrance float off the ground and merge together into one before crashing into the entrance, molding into the wall. Sealing Kylo Ren off from them, and them from him. The resulting tremor is so powerful that the very ground shakes beneath them, that Luke can hear parts of the Crystal Caves collapse in on itself. Dust billows everywhere, and Finn staggers; Rey manages to catch him just in time.

Finn's face is sweaty from exertion. "Did that kill him?"

Luke shakes his head. "We aren't that lucky," he says, his voice a rough deadpan. Han would've been proud. "Come on. Let's get out of here."

"Any word from the others?"

Finn looks up from the communicator in his hands, and makes room for Rey to sit beside him in the passenger row behind the cockpit. Luke is steering them off the planet and into hyperspace, but puts the ship on autopilot so he can listen. "I haven't tried yet," he says. "I don't know what to tell them — if we should warn them about Kylo Ren or not. But if he attacked us, he might come for them next."

"I don't think he was there to attack us," Luke says, and Finn startles.

"How do you figure?"

"He looked surprised to see us," Luke says. He sounds as exhausted as Finn feels — but a brush with certain death will do that to a guy. "But that was all. Even when he had me cornered, he didn't think of me — or any of us — as anything more than a distraction from his true purpose."

Rey breathes in sharply. "That bag," she says, her voice a little unsteady. She unholsters her new lightsaber and turns it in her hands clockwise, then counterclockwise. "He had a bag of kyber crystals on him. He stole them from the cave."

Finn takes a deep breath, trying to calm his racing heart. "What would he want with more kyber crystals?" he says. "He has his own lightsaber. Clearly."

Luke bites his lip. "I don't know," he admits, which does not help Finn's nerves. The stars around them begin to blur as they make the jump into hyperspace. "But I have a feeling we'll soon find out."

Stay tuned for Chapter VI, in which Poe's team arrives on the Messenger, small complications arise, and the fuse of full-scale mutiny is lit at last.