Everyone in the underground knew their king, Asgore Dreemurr, loved flowers with a passion. It was pretty obvious considering that his throne room was a literal flower garden.
So, obviously the two royal siblings, Chara and Asriel already knew what they were going to give him for his birthday.
"Hey, Chara, how about this one?" The goat boy said, pointing at a slightly beaten up Echo Flower
"Hey, Chara, how about this one?" The Echo Flower repeated
"Hmmm, no. It's pretty roughed up." The human said, looking around to find another flower
"Hmmm, no. It's pretty roughed up" The Echo Flower repeated
Of course, you'd think they would simply go to Asgore's garden and get some flowers. But where's the merit in that? Plus, Asgore probably wouldn't like getting flowers from HIS garden since he planted them.
They chuckled at the flowers' shenanigans and kept going until they found a hallway with Echo Flowers, waterfalls, weird glowing floating things and some signs about the barrier and the monsters losing hope. Chara, curiosity besting them, started reading the signs.
"Charaaaa. Maybe we should hurry and get dad's gift." Asriel whined
"No need to hurry. We probably won't come back here for a long time so, why not have a look around?" Chara said, winning the argument
Asriel folded his arms and pouted "Fine." The Royal Prince said giving his Royal Sibling the permission to read. Chara started to read while giggling at Asriel's pouting face.
"Hurt, beaten, and fearful for our lives, we surrendered to the humans. Seven of their greatest magicians sealed us underground with a magic spell. Anything can enter the first seal, but only beings with a powerful SOUL can leave." Chara read.
Asriel started getting interested, so he read the next one "There is only one way to reverse this spell. If a huge power, equivalent to seven human SOULs, attacks the barrier... It will be destroyed."
Chara started to get thoughtful as they read "But this cursed place has no entrance or exits. There is no way a human could come here." Chara's eyes widened at the last phrase
"We will remain trapped here forever."
Realization hit the red souled human as they realized— this was partly their fault. They are human. They are one of the kind who trapped their current family down here— the family who saved them and gave them a home— to rot and die. They were responsible for this.
"...Chara..." They heard echoes of their name and got confused. What is this? Are the souls of the ones they killed calling out to them? "Chara...Chara...! CHARA!" The human's eyes opened quickly and they gasped, finally coming out of their trance "Are you okay? You spaced out for a minute there." Asriel said, eyes full of worry and hands on Chara's shoulders. It appears they had been shaking Chara for a while.
Chara was silent, thinking of something to say as they turned to the heir of the Underground "A-Azzy...Is this my fault? Are you all suffering because of me?" Chara said. It was evident in their tone that they were shocked and depressed. Asriel looked at Chara and didn't even have to think to know what to say.
"Of course not, Chara!" The young boss monster said without fear to shout. Chara turned to them, obviously surprised "Even if humans did this, that doesn't mean you were like them! It isn't your fault if you weren't there!" The second heir to the throne needed a few seconds to let the words sink in and, when they did, they smiled, and it was the brightest smile Asriel had seen Chara do "...Thank you. I'm sorry I'm being such a crybaby." They both laughed at Chara's nickname for Asriel getting turned to them "Now let's keep looking for better Echo Flowers." The cheeky human said, but Asriel stopped them "Wait. Can't we reach those flowers?" He pointed at the Echo Flowers behind the signs "I don't think we can reach those." Chara said, thoughtfully "It doesn't hurt to try!" Asriel said as they charged towards the flowers...and faceplanted on an invisible wall "Pfffttttt! Wait what?!" Asriel said painfully, as they were rubbing their hurt goat nose. Chara was laughing so hard they looked their eyes were gonna pop out. "Hey! It's not funny!" Asriel said and succeeded to keep the seriousness in his face...before he burst out laughing too. They stayed like this for a few minutes.
"That was so funny from my perspective, you don't even know!" Chara said while laughing and gasping for air. After a while the two stopped laughing and decided to move on.
They found a glowing mushroom puzzle. Due to their ability with puzzles thanks to their mom's books, they completed it in less than 15 minutes. Next there was another puzzle with fading lanterns. They needed to have quick feet if they didn't want to get trapped in the dark, but the reward was worth it. They passed the puzzle and went to the next room. Only to find a beautiful alleyway full of Echo Flowers and glowing sparkles that looked like stars.
"..." Upon finding it, Chara gasped and Asriel's jaw fell wide open; Although the room was beautiful, the flowers were even better. They looked beautiful glowing in Waterfall's darkness, plus they were perfect, none of their petals were missing, they were perfectly firm, they didn't have any scratches...It almost looked as if no one ever passed here, and they were able to grow in peace, without any nuisances or other living beings. They almost felt bad that they had to pull them off the ground, but this was for their father.
While Asriel was pulling out a few of them from the sides, Chara glanced at the sign and read it quietly, without Asriel noticing.
"However... There is a prophecy. The Angel... The One Who Has Seen The Surface... They will return. And the underground will go empty."
* (You hear a passing conversation.)
* ... hmmm... if I say my wish...
* You promise you won't laugh at me?
...
* (You hear a passing conversation.)
* Of course I won't laugh!
...
* (You hear a passing conversation.)
* Someday, I'd like to climb this mountain we're all buried under.
* Standing under the sky, looking at the world all around...
* That's my wish.
...
* (You hear laughter.)
* ... hey, you said you wouldn't laugh at it!
...
* (You hear a passing conversation.)
* Sorry, it's just funny...
* That's my wish, too.
"Happy Birthday!" They all shouted in unison, including the bouquet of flowers. King Fluffybuns was smiling so much that he couldn't hold his tears. They were like waterfalls, he could probably aliment his whole kingdom with all of those tears.
Chara looked at the bouquet of flowers repeating 'Happy Birthday' almost like whispers. Maybe they would pay for their redemption. Maybe they would become the Angel. But not today. Today, they will enjoy the life they had, as if it was the last day. Not today.
They glanced at their family, hugging their so-called 'Mr. Dad Guy', and smiled.
"Not today..." They whispered, almost at a lower volume than the flowers.
"Not today."