"Master Skywalker," Rey says, "please come back. We need you."
The words catch in her suddenly dry throat. She's seen too many living legends in the last whirlwind days to be truly in awe of him, but he's still Luke Skywalker. The last Jedi, the strongest, the strangest, a campfire tale told in whispers after the dark now standing before her in the flesh. She isn't afraid of him, but oh, how afraid of him she is.
"Child," he says, calmly, "you don't know what you're asking for." He doesn't take the lightsaber she's holding out, and she fiddles with it awkwardly, not quite ready to lower it.
"I know that we need you. The Resistance... your sister..."
"Come here," he says. "It might be easier to show you."
She goes to him, warily, to stand by his shoulder. All she can see is the ocean, an incomprehensible expanse of water stretching from one edge of the world to another.
Master Skywalker says, "Now watch very carefully, and don't be afraid."
He stretches out his hand - his metal one, the one that looks eerily skeletal - towards the horizon, and closes his eyes. Nothing seems to be happening at first, but then the ocean's placid surface starts changing. The water starts to swirl, first in slow lazy circles, then faster and faster, twisting into gigantic vortex, swelling higher and higher. A tower of water rises, higher than the trees of Yavin IV, higher than Maz Kanata's castle, higher than anything she's ever seen in her life, vast and horrible, rises until it touches the sky. She screams and can't hear her voice, even though there's no other sound in the air, no sound at all, and she feels the Force swirl inside of her in response, neither light nor darkness but an ocean.
Then Master Skywalker lowers his hand, slowly, slowly, and the tower does not collapse but dissolves back into the waves, serenely and quietly, not a single drop of water falling carelessly. In but ten minutes, the world is as it's been, except for her who's been irrevocably changed. She drops to her knees, panting for breath. Master Skywalker sits down next to her, in the careful manner of an old man with creaking joints and aching knees.
"In the Force," he says, "there's no difference between a single drop of water and an ocean, or a stone and a mountain, or a mountain and a planet, or a planet and a star. Do you think I'm hiding from the universe here, dear child? I'm hiding the universe from my anger."
Rey doesn't need to ask him what he means: she hears it clearly in the Force between them, screams of his slaughtered pupils, Han's last agonized inhale, Jedi Temple's walls crumbling. Decades of fighting and building and growing things, wiped out in an instance, again and again and again.
She wants to run away. Down the green hill, down the stone stairs, back to the sanity of spaceships and blaster shots and reckless rescues, back maybe even to Jakku with its hunger and desperation and desert and not a drop of water in sight. But Finn is still laying back there, still as death, and Han is still dead, and General Organa is sitting somewhere with her head in her hands, and the ocean of Force all around her is still singing, its green waves beating against the shores of her mind.
"We have no choice," she says. "Anger or not, you'll just have to - make do, like all us. If you sit here a bit longer, there will be no universe left for you to be angry at."
He's mute, unmovable. "Please," she says, "please. Teach me to stop you if you need to, and I swear to you I will, if it comes to that. But, come."
"Oh, child," he says, "this is why Leia sent you, isn't it," and then suddenly laughs, throws his head back, a startlingly young sound. "Oh, well. Go down and bring Chewbacca back here, will you? We might as well have some tea to start with."
She leaves the lightsaber in the high grass next to him before she goes.