((Prompt: Write a sequel to a story that ended with “She closed the gate behind her, confident she would never need to open it again.”))
A cold, late autumn wind blew across Rarity's coat as she stood facing away from the rising sun. She shivered and tugged her scarf tighter around herself. She was at the very edge of Ponyville. Where she stood now was still home, still safe and comfortable. A step ahead of her was the world, waiting to swallow her up into its endless expanses.
A scrap of paper hung in her magic grip, glowing a cool blue against the dawn's warm yellow rays. It was what Pinkie had left her with. She had dropped Gummy off at Fluttershy's cottage. Left a sack of bits on Applejack's doorstep that the farm mare had forgotten she was even owed. Returned all her books to the library, and left all her pranking things in a pile beneath Rainbow Dash's cloud house. But at Carousel Boutique, Pinkie had only slipped a mouthwritten note under the door.
'I'm sorry. Goodbye.'
Rarity took a deep breath and folded the note, tucking it into a pocket in her saddlebags. She was dismally underprepared for a journey. Rations for a few days travel, only the most utilitarian of clothing—by anypony's standards, even, not just her own definition of necessary attire—and a few bits in case of expenses. The Boutique was locked up with a sign indicating it would be closed for an unknown amount of time. Fluttershy would take care of Opal.
The others wanted to come with, of course. Rainbow had been especially difficult to convince she needed to stay. Her training with the Wonderbolts started soon, and while her loyalty was commendable, there was simply no reason she should have to lay down her dream when it was something that Rarity needed to do herself.
And she did need to do this herself. Though the girls denied it, it had been Rarity's actions that had driven Pinkie away. Rarity needed to set it right. And just maybe she had her own reasons for wanting to find Pinkie herself. Perhaps she wanted to be the pony there for her, to convince Ponyville's heart that they couldn't go on without her there. Just maybe she had some questions of her own that only Pinkie Pie could answer.
Rarity steeled herself, and put her hoof across the town line. She let out a sudden exhale. She was on the road now. Equestria was before her, and somewhere in it was a pink pony without whom the town she had just left wasn't truly home.
She had an inkling of where to start looking. She adjusted the fit of her saddlebags as she marched down the winding road. It was a long way to rock-farm country.