Half the Day is Night
"You see?" Luna asked, her gossamer diagram spinning above the center of her room, the spark in her voice making Celestia smile. "It'll be just like what we were doing before except now we'd announce the dawn and dusk there in the center of the courtyard where as many ponies as possible can see it instead of each of us going back to her throne to make it happen." She grinned with an eagerness Celestia hadn't seen in her for a long, long time. "Whaddaya think, Sunny?"
Celestia cocked her head. "I think my vacation did you more good than it did me."
Luna laughed. "I think you're right." Her smile faded. "It's just...we owe them so much, all those ponies, and we can't...I mean, they can't...they don't-" All her previous good humor disappeared, and Celestia's shoulders tightened. Could it finally be time?
She leaned forward, touched her nose to Luna's neck. "Starry? What's wrong?"
Her voice came out as the barest whisper. "How, Sunny? How can we be friends with them when someday they're all going to...to-" She choked off and turned her head to meet Celestia's, her distress darkening the glow of her horn.
Yes, it was time. "Like this," she said softly, and flexing her neck to bring her horn into contact with her sister's, she cast the spell she'd been longing to share with Luna for a thousand and one years.
Luna's room vanished around them, the dark of the early evening sky outside replaced by a stranger darkness, a velvet quality to it that Celestia had only ever found in this place. "What-?" Luna asked in alarm, stepping back, looking around, the silver aurora of her mane suddenly spiky. "Where-?"
"It's all right," Celestia said quickly. And it was better than all right, the tree beside them exactly as it should be, the grassy hills rising up on all sides to create a little valley under the soft violet light of the sky. "This is the Grove, a place I found at the end of that horrible, horrible first week after I'd sent you into exile, a place I once thought was a dream, but now...now I know it's not."
Still looking around, Luna seemed to have lost most of her panic. "It feels so...so welcoming somehow." She turned to face the tree, and Celestia heard her gasp at what-or rather who-was lying there asleep: Twilight Sparkle and her friends, just as Celestia had expected, but also Ory Stargazer and his mother. Which made sense, Celestia decided.
"That-" Luna swung her head from the sleeping ponies to Celestia and back again. "That isn't really them. Is it?"
"It will be." And for all the time Celestia had had to plan, she still wasn't sure how to explain this place to Luna. "I first found my way here the night after we'd gotten the stars I'd managed to blow out back into the sky. I saw all the ponies who'd helped me, all the ponies I now thought of as my friends, all sleeping under this tree just like this."
The quiet made her whisper, but Luna's pricked ears told her she was catching every word. "And then...then the next week, Swampy, one of the old earth ponies who'd shown me how to get the marsh gas burning, she died, and after the funeral, in my grief, I sought this place out again, wanting only to see her safely asleep, and instead...instead when I arrived here, she...she was awake, Starry. She was awake, and she knew me, knew everything she should've known, was herself, her real self, here...forever..."
Luna was staring at her. "You mean...she's here now?"
Celestia pointed her nose to the hills around them. "Just over the crest with everypony else who's awake. At least, I'm guessing: this is your Grove, not mine. But it feels the same here, so I'm betting mine's not too far away."
"Then-" Luna kept looking back and forth. "Any mortal friends we make, they...they come here after they die?"
"They do." Celestia couldn't keep the excitement out of her voice. "And any friends our friends make, they'll show up as well! My Grove is a huge valley filled with sleeping ponies, dragons, griffins, every living creature who's ever made a friend, a chain linking back a thousand years with me in the center! And with two of us out in the world now-"
"But Twilight and AJ and everypony!" Luna's horn glowed black in confusion. "Aren't they already in your Grove? And...are you saying-" Light danced in her eyes. "You're saying I can meet the ponies who helped you with the night all the time I was gone?"
Celestia flared her wings. "Let's go see," she said.