The three royal children were on their flying horses racing with each other to see who's the fastest.

The one ahead is a boy with blonde hair with brown eyes wearing a green shirt with black buttons on them and yellow pants, is on his red flying horse. The girl right behind him who's flying a small purple horse has short brown hair with blue eyes wearing a purple and pink dress around her neck is a pink necklace. The last one behind the girl looks similar to the boy has long blonde hair wearing a yellow golden dress with little sparkles on the dress.

The boy shouts out to the girls behind him, "catch me while you can?!"

The girl with the blonde hair spoke, "not if I can help it!"

She made her white and brown horse go a little faster to catch up to the boy. The boy saw his twin sister was trying to catch up. He had his horse to go even faster.

"Hey" shouted the girl, "not fair!"

The boy shrugs as the two try to beat one another. The girl with the brown hair shook her head as she saw her horse began to get tired.

"Getting tired Minimus," ask the girl.

Minimus took a deep breath, "Y... yeah, I am Sofia."

Sofia nods as she landed Minimus to a well-landed place on the mountain. She looks around knowing that she had never recognized this place before.

"I never been here before," said Sofia as she looks down at the glorious view.

Minimus nods as he found a puddle of water to drink from. Sofia happens to look to her side to see an entrance of the cave not far from where they are at.

With her curiosity, she began to go near the entrance. Minimus stop drinking to see her going towards the cave.

"Hey Sofia, what are you doing?"

Sofia respond, "I'll be right back need to check something out."

Minimus started to drink again as Sofia got into the cave to see it was dark. She looks around the only thing that was shining in the cave is the sunlight itself. Sofia looks around as she didn't see the big hole up ahead of her.

As Sofia got too close to the edge the rocks began to fall and cause her to fall into the hole. She caught herself at the edge of the cliff as she screams in terror.

"Help somebody please!"

But nobody came.

As she held on the cliff for her deal life, she looks below to see a dark black pitch below her. She was frightened that if she let go then she'll fall to her death.

Just then the rocks began to crumble to where she was holding and soon broke off causing her to fall. She screams as she fell down, down, down, into the bottom of the ground. Not knowing if she would ever make it.

Soon she hit the ground hard causing her to knockout. She lay there for a long time till finally, she began to open her blue eyes as she felt something underneath her. She looks to see she was laying on a patch of golden flowers.

She sat herself up really fast to see that she was in a whole different world.

"Where am I?"

Sofia got herself up as she brushes her dress some before walking to a nearby hallway.

"I wonder where this leads to?"

Sofia begins to walk through the hallway as she can see it was pretty dark. As she thought there might be no way out that's when a small flower perk out from the ground causing Sofia to jump seeing little light reflected somehow on the flower.

"Howdy," said the yellow golden flower with his fangs sticking out from his mouth, "I'm Flowey, Flowey the flower... wait a second..."

Flowey look at Sofia over and then his eyes hole widened, "you're a princess! A human princess from the surface."

Sofia nods as she sees Flowey playfully tugging at her dress.

"Well you know I'm also a royal too. I know it's silly to think a flower like me would be a royal just like you. Well, I don't know how many other monsters like me would realize you as a princess but at least I did."

"Wait you mean there are more?"

Flowey looks up at Sofia's surprise and curious face expression as he looks deeper into her blue eyes.

"Why of course silly. This is the Underground where monsters like me live."

Sofia understood what Flowey was saying though she never knew monsters would want to live Underground. Flowey looks a little lower as he spotted the necklace around Sofia's neck.

He gasps as he saw the necklace knowing what that is.

"Is that the amulet of avalor?"

Sofia looks down but then got a bit suspicious of what Flowey ask.

"Y... yes, how did you know about that?"

Flowey giggles, "you are too silly Princess, I told you I'm royal I'd also had to study magical things like that amulet of yours."

"So you know what kind of magic it can do?"

Flowey nods, "well of course I do. Even the king knows about it."

"You're father?"

"Guess you can put it that way but no matter. I'm sure you're lost wondering how you got down here. Leave it to little old me."

Sofia looks down to see a red and purple mix color heart floated in front of her. She was so confused at it till Flowey finally explains to her.

"You see that heart in front of you? That is your soul."

Sofia tilts her head as she stares at her soul, "I never knew souls would look like a heart."

Flowey giggles as he ignores Sofia's curiosity of her own soul, "well now your soul must contain LV. What's that stand for well LOVE of course? It's how it works down here."

Sofia looks at Flowey and nods thinking he meant love as in feeling for others not the other kind of LOVE.

Flowey then shows Sofia some white tiny pellets floating all around her.

"Those are friendly pellets of mine. Go ahead and catch one. It's a little game I like to play with others down here."

Sofia got up as she saw her soul going back into her body. She looks up at the pellets and began to jump up to catch one. As she grabs one she felt pain rush through her hand and into her arm as she fell down on the ground.

"Ow, that really hurts."

Sofia looks at Flowey as his face droop downwards his whole face was so terrifying for Sofia to look at. Even when he spoke his voice was deeper than normal.

"In this world, it's kill or be killed. You are such an idiot to think I'll spare you, Princess. Now it's time for you to die!"

As the white pellets began to swirl around Sofia she screams as she covers her head with her hands. Flowey laughs as the pellets began to get closer to Sofia. But then...

Flowey turns to see a huge fireball strike at him causing him to fly into a wall. Thankfully he really doesn't have any feelings since he doesn't have a soul at all. Yet it wasn't fun flying either.

Sofia began to shake as she heard a woman's voice saying, "what a terrible creature torturing such an innocent youth."

Sofia didn't look up to see who or what had just saved her from Flowey. She fears this woman is after her too just like Flowey. Soon Sofia felt a warm paw brush against her hair. Her tears draining down on her cheeks.

"Please, my child," said the woman, "do not fear me for I won't hurt you."

Sofia sniffles as she spoke, "h... how do I know you won't hurt me?"

"Oh my child, I'm so sorry that mean flower had tried to hurt you. But I promise I will never harm you. You are safe as long you are with me."

Sofia finally looks up with her eyes red from all the tears she spread across her face. There in front of her kneeling down is a white female goat monster with little fangs from her mouth as she wears a long purple dress with a white symbol on her dress.

"W... who are you?"

Sofia sat herself up as she asks the goat monster her name.

The goat monster smiles warmly at her, "I'm so terribly sorry for not introducing myself right away. I am Toriel the care keeper of the Ruins. I come by here to see if any humans have fallen down here."

"So I'm not the only one who fell down here?"

Toriel shook her head, "no my child, there has been some who came before you. Yet they are not here with me no more at all. I'm sure I'll never see them again."

Sofia thought maybe Flowey had killed them all after Toriel took them. She didn't know the whole story of the Underground yet.

Toriel smiles, "come, my child, let's not wait much longer. I'll show you around in the Ruins. There are many puzzles you must solve in order to get by here."

Sofia took Toriel's hand as Toriel help Sofia up. Sofia knew that this goat lady was indeed trustworthy. She is so kind and gentle almost like... Sofia then thought about her mother. How much her family is going to miss her when they find out she's gone.

Sofia smiles up at Toriel as she kept hold of the warmth of Toriel's paw. Toriel looks down as she too smiles back. Sofia and Toriel began to go further into the Ruins.

AN: So guess being a little crazy to do this crossover story. As you, all have read my previous series of Under Universe Tale. This story is sort of like that story but a whole different perspective and yes, Sofia is a princess so things maybe a bit different for Sofia not by much, though. Since she's a human and all. Well anyways hope you like this chapter. There will be more to come. I'm super excited to do this story!