Usually she'd put comparatively little stock in millennium-old legends, but this is a primary source, and the authors made some correct predictions on other matters, and the translator is good, and she double-checked to make sure the page numbers matched up so no one has been pranking her with inserted extra leaves. And the prediction is fairly dire.
And it's rather short notice.
Clarity tucks the book into a saddlebag and trots up to the main section of the palace. She can usually get an audience fairly quickly; Celestia has taken a particular interest in her since her admission to the School for Gifted Unicorns. This day is no exception. In fact, the guards usher her in even quicker than she'd usually expect.
"Princess, I have something urgent to tell you," Clarity says, mid-bow.
"Oh? What is it, Clarity?" inquires Celestia.
"I've found a prediction stating that on the longest day of the thousandth year -"
"Clarity," sighs Celestia.
Clarity grits her teeth; she's never told Celestia not to interrupt her. You can't tell the princess that. "Yes, Princess?"
"I have the utmost respect for your diligence at your studies, but you've got to take your nose out of those dusty old books now and again," says Celestia with a warm half-chuckle. "There's more to a young pony's life than studying. You're in the prime of your life, you're coming up on the end of what you can learn from school -"
Clarity stands up on all fours, no longer bowing, jaw slightly open.
"And," continues the Princess, "you need to make some friends. I worry about you all alone, you know. Weren't you invited to that party - who was it, Moondancer?"
"Yes, I was invited, but I barely know her," says Clarity.
"Perhaps the ponies around Canterlot just aren't clicking with you. You know what," says Celestia, as though seized with sudden inspiration. "I'm going to give you a job to do."
"...a job, Princess? But what about the longest day of the thousandth -"
"Clarity," says Celestia again, and Clarity shuts her mouth. "Don't you worry about it. I'm sending you to supervise the preparations for the Summer Sun Celebration. It's being held in Ponyville this year. I'll arrange a carriage for you. Pack your things, you leave in two hours."
"I..." Clarity can't really gainsay her. "Yes, Princess."
Celestia smiles.
Clarity bows again, and leaves, and packs.
-
She's in the air, drawn with her luggage in her carriage by someone in good condition for a long-distance flight - they're still working on that train line.
She steps onto the main street of Ponyville, laden with all her possessions in her saddlebags, and levitates her to-do list in front of her nose.
"Okay," she sighs to herself, peering at the first item. Clarity is pretty sure Celestia has read every book in the palace library at least once; probably she investigated the danger well in advance and dismissed it. (But Clarity will be staying in a library while she's in Ponyville, so she'll have a chance to double-check and find corroborations once she checks out the Summer Sun Celebration preparations.)
"First," Clarity mutters, "banquet preparations. Cheery Cherry Orchard."
"I'm glad to hear they're doing well, though I'll still want to look in on them personally. Is it all right if I sample one of the extra cherry danishes?"
"Well, this is excellent. If everything else is to the same standard of quality then you've more than met expectations on this."
"I know where to find the best cooks," says Cordy. "Did that list come with a map, or would you like directions to the rehearsal?"
Cordy nods. "If you head back to the road and turn left, away from Ponyville, then keep on going down the main road until you see a side road on your right opposite a pond on your left, rehearsals should be a little ways down that side road. I can get that written down for you if you prefer."
"I've got it," says Clarity, who always has a pencil and a notebook on her. "Back to the road, left, side road on the right opposite a pond. Thank you very much. Can I have a spare carrot slaw to go?"
And so Clarity waves and floats a carrot slaw in its little bell pepper bowl from its friends and trots off back to the road, where she turns left, turns right, and proceeds onward from there. While munching both slaw and bowl.
The rehearsals are taking place at a stately old tree just past a low hill; the birds perch in the branches, while a grey pegasus with a bi-coloured silver mane sits beneath the tree and plays her violin. This must be Silver Streak. She's very good.
Rather than interrupt the music, Clarity waits nearby to listen to the song. It's very pretty and the mood is appropriate for the celebration. (Her slaw is gone now, so there are no impolite munching noises.)
"Good afternoon," she says.
"Hello. I'm Clarity Bell, and the Princess sent me to oversee the preparations for the Summer Sun Celebration. It sounds like you have everything handled, music-wise?"
"Entirely," she agrees. "It seems you have inspected the food already; what remains on your itinerary?"
Clarity looks down at her front to see if there are crumbs or bits of dressing in her fur, but sees nothing. "Uh? ...Next I'm planning to look in on the decorations, to give whoever's clearing the sky extra time to get it done before I'm breathing down their mane." She peers up at the sky; it's not exactly crowded with clouds, but it doesn't look cleared.
"That would be my sister Brightblaze. When you're done inspecting the decorations, you'll find her in the tower on the far side of town, immersed in some project and having thereby forgotten what time it is and possibly what day. But it will not take her long to clear the sky, so as long as somepony reminds her with a few minutes to spare, all will be well."
Clarity writes down these directions. "If you're that sure she's forgotten perhaps I should just visit her next anyway."
"The town hall is directly between here and home, along the main street; you won't lose anything by stopping there first," she explains.
"All right. Well, don't let me keep you from rehearsing any more," says Clarity, and she turns to go.
"Goodbye," says the pegasus, and she picks up her violin again and turns her attention back to the choir.
Off Clarity trots towards the town hall. She is well ahead of schedule and should have plenty of time to research the warning.
The town hall looks pretty decorated! Appropriate sun symbol banners are hung from hither and yon, and streamers and crepe paper are strewn and elaborately knotted around other things, and the unicorn who seems to be handling this is in the process of arranging flowers to tuck into convenient loops of ribbon left when the bows were tied. "Oh! Hello!" she exclaims when Clarity approaches. "I'm Guiding Star." She slots a bouquet of camellias into a bow and cinches it up, then nods at her work and lets the golden magic fade. "You must be Clarity! Joy said you were going to come check things over. What do you think?"
"It looks pretty close to done, very tasteful, very neat... What else are you planning to add in the time you have left?"
"Well, all the bows are getting flowers. Do you think we've gone overboard on the colors? The florist thought we were going overboard on the colors. The idea is that the main color in every bunch of flowers matches its ribbon and the others complement it, and as you can see the ribbons are arranged in rainbow order."
"I probably would've been skeptical if I'd gotten a pitch in advance but it seems to be working okay in practice. Is the interior similar?"