If you tell something to the Echo Flowers, it'll repeat it. If you tell them your secret desire, it'll come true. Everyone in the Underground knew this story, no matter which AU. Not everyone believed this, but they still did it anyways in hope that it'll come true.
This was especially true for Red who came from Underfell. Echo Flowers that granted your desire? Lies. Yet he went to where the most flowers grew most. It always gave him a small light of hope. He used to have hope for the human who would free them all. Turned out, it was all a lie. He was just a program in a game.
A game. Was that all he was? No matter which route, or the amounts of resets, he always had to go visit the large garden of Echo Flowers that grew near the river. Even if he probably had already been through it all. That is until one out of few Pacifist routes later he met him.
Sans. He found a skeleton that looked like himself sitting in the garden of Echo Flowers. He looked just like Red. Minus the pointy teeth, wore a blue jacket, didn't seem as beat up as Red, and was smaller. God he was cute.
Red shook his head, "No, what am I thinking!? You have to get them out of here or kill them before your brother punishes you again." He winced at the thought of his brother. He had protected him when they were little, yet he never really returned the favor.
Unless of he counted his brother making everyone fear him and hate him, so that supposedly they wouldn't hurt Red. Which he did of course although it just made matters worse he still appreciated it.
But this skeleton, would probably change him for the better. Even if Red didn't know it yet, he would feel his own start of actual love.
"Who are you!? What are you doing here!?"
The other skeleton looked up at him, "You must be Red right? This is Underfell?" Red was confused by what this skeleton was talking about. And maybe his smooth pleasant voice. He shook his head. "Who are you?" He was starting to get flustered, he couldn't let this intruder see that.
The smaller one started giggling, "Your face is going red. Red." The smaller skeleton started laughing. Red was starting to get frustrated.
"Shut up and tell me your name already!"
"My name is Sans. I'm the original Sans. Your AU is really mean and harsh. And I'm sorry about your brother. I couldn't expect my Papyrus could ever do that. But, you're a good brother. You've taken very good care of him, mind the circumstance of living in this AU."
He turned around and faced Red. He placed his hand on his amd stared at him. He then smiled and said in a gentle yet slightly sad voice.
"You're a good brother. I know that for sure."
Red started getting even more flustered and looked away. Sans could sense this and decided to distract him with something else.
"You know if you tell an Echo Flower your secret desire it'll come true?"
"Of course I do. It's the same story here. Except it doesn't come true. No one's tried it since they don't believe in that crap."
Sans stood up and smiled down at him, "Welp I have to go back to my AU now."
A type of glitchy hole opened up and before Sans walled into it he said.
"Also, how will you know it's not true if you've never done it."
He then dissapeared through the portal as Red stared after.
Red then looked around to see if any monsters were around and went to one of the Echo Flowers. And whispered:
"Thanks for making it come true..."