Most Likely to Get a Clue

Sunset Shimmer stretched and yawned. She had just finished looking through another enormous, boring book about the history of Equestria. She closed it with a thud.

“Did you know,” she told Princess Twilight, “that Chancellor Puddinghead tried to pass a law mandating Earth ponies drink carrot juice at every meal? I do. Now.”

“Awww,” Princess Twilight said, smiling happily. “Sounds like you got to read all the fun books. We should probably take a break from looking.…”

Sunset Shimmer sighed, tired and disappointed.

“Because,” said Princess Twilight, about to burst from excitement, “I found something!” 

Sunset Shimmer couldn’t believe it. Princess Twilight pranced up and down the aisles. She levitated a large wooden box over to a table and pulled out a few scraps of old parchment. She arranged them carefully on the table like puzzle pieces.

“You are familiar with the Seven Trials of Clover the Clever?”

Sunset Shimmer tried to pretend as if she were. “Uh, obviously. But, uh, let’s see how much you know about it.”

Princess Twilight wiggled happily. “Well! First of all, these date back to before the founding of Equestria.”

Sunset Shimmer knocked on the box. “I’ll try not to break it.” Almost immediately, she realized that Princess Twilight was not in a joking mood. “I’m kidding,” she said.

“Look at this,” said Princess Twilight. On one piece of parchment was a drawing of a strange gray obelisk. It stuck up into the air like a pointy tower.

“The Memory Stone,” read Sunset Shimmer. “That sounds promising.”

Princess Twilight shared everything she had found out. “It belonged to an evil sorceress who was practically invincible. With the Memory Stone, she could erase any memory from anypony. Even fragments of memories.”

Sunset Shimmer thought out loud. “Fragments like… memories of me being nice?”

“Clover the Clever knew the sorceress had to be stopped,” continued Princess Twilight. “And the Memory Stone had to be destroyed, so he chased the sorceress across land and sea. But every time he got close, the sorceress would erase his memory and escape. But he kept finding her.”

“How?” Sunset Shimmer wondered.

“These scraps of parchment! He secretly wrote everything down so he’d know what had happened and where to go next, even as he constantly lost his memories. Like a trail of bread crumbs.”

“That’s clever!” Sunset Shimmer grinned. “No wonder he was called Clover the Clever!” She studied the scraps of parchment. On one of them was drawn what looked like a swirling portal. Clover the Clever was chasing the sorceress through it.

“What happened on the other side of this portal?” asked Sunset Shimmer.

But Twilight didn’t know. “The last page is missing. Clover must’ve hidden it to keep anypony else from finding the Memory Stone.”

Sunset Shimmer studied the portal. It looked familiar. It looked just like going through the Wondercolt.

Princess Twilight thought the exact same thing. “What if the Memory Stone ended up in your world?”

“And what if,” Sunset Shimmer continued, “someone is using it to make everyone hate me again?”

“But who?” exclaimed Sunset Shimmer and Princess Twilight together.

That was the question.

Who would have the magical power and the motive to divide Sunset Shimmer from her friends?