"Erase all the sad memories, hold onto my hand and smile," 

- Two, Three (BTS) 

The halls of Shin A High are filled with the sound of chatter, students in matching uniforms mulling around. The newest addition to Sky Castle, Hwang Woo-joo, is being given a tour by the Cha twins.

"And there's the observatory," Cha Ki-joon said, voice bored. His hands are shoved into his pockets, tie loose and shirt untucked from his trousers. His brother, Cha Seo-joon is the complete opposite, blazer neatly buttoned up, tie knotted up, uniform pristine.

"You guys even have an observatory here?" Woo-joo asks, surprise coloring his tone as he looks at the large room, a telescope visible even from afar, the sky visible from the glass that surrounds it. "Wow. Rich kids really do have everything,"

"There's a reason as to why the tuition fees is so high," Seo-joon replies, smiling in amusement.

"Do all of the children from Sky Castle go here?"

"Yeah. It's pretty much tradition to send us kids here, because of how the school has a pretty good reputation,"

"Have I met everyone from Sky Castle?"

"Not everyone," Woo-joo blinked, turning to face the two brothers. "You know the house that's been locked up ever since you came here? A family actually lives there, but they went away for some business,"

"Really? Who are they?"

"The Songs. One of the most prestigious families in all of Sky Castle," Woo-joo tilted his head, listening intently. "They've been living at Sky Castle ever since it was made. The earliest Song actually helped design and build Sky Castle, which is why they're adored by everyone living there now,"

"The Songs have always lived at Sky Castle, at the grandest house in the entire neighborhood. Right now, Song Sang-hoon is the head. He's a very prized engineer, having graduated from school that has a name I can't even pronounce,"

"It's that fancy," Ki-joon nodded solemnly, snickering at how Woo-joo's eyes widened.

"They're a five member family. Song Sang-hoon and his wife, Song Ara. They have three kids. The eldest is their son, Song Sang-jun. He used to study at this school too, but graduated and attends SNU medical,"

"Sang-jun hyung's really cool," Ki-joon said. "He's quiet and doesn't talk much, but he's always taking us wherever we want and making us laugh with how honest he is,"

"The youngest daughter is Song Hana. She's about Ye-bin's age, short and really bubbly. She's known to be one of the smartest kids at our school, but struggles with her Korean because she used to live abroad with their mom when she was younger,"

"That's just two kids. Who's the third one?" Seo-joon's smile widened at this, looking mischievously at his brother.

"Oh I saved the best for last. As Ki-joon usually says, she's the most important member of the family," Ki-joon turned red, shoving at Seo-joon, flustered for the first time ever.

"She?" Woo-joo echoed.

"Song Yuna," Ki-joon answered, gaze faraway and eyes lit up in a way that Woo-joo has never seen before, soft and fond.

"She's the middle child, and is the same age as us. Yuna-ah's actually in our class. She's really bright and cheerful, and generally considered a troublemaker, but everyone loves her too much to say anything,"

"She's friends with everyone. Nobody dislikes her. She's sweet and kind-"

"-and an annoyance but we adore her," Seo-joon cuts in. Ki-joon nodded in agreement. "Not only that, but she's usually in the top five of students, usually competing with Ye-seo and Hye-na. But she doesn't take studies as seriously as them,"

"She sounds like fun. When is she coming back?" Seo-joon opened his mouth to reply, when a shout interrupts him.

"Song Yuna! Come back here right now!" Ki-joon's eyes widen, and they all spin around to find a girl turning around a corner. Pink hair streamed behind her as she ran, glancing back every five seconds to laugh at the teacher chasing her. Her blazer is tied around her waist, and her skirt whipped against her legs. They stared as she ran past them, running up the stairs to their classroom. Seo-joon and Ki-joon exchanged glances, faces turning nonchalant as the teacher comes to a stop in front of them, looking around angrily.

"Have you three seen Song Yuna?"

"Yuna-ah?" Seo-joon has a faux surprised expression on his face. "Why would she be here Mr Kim? She's in England, right?"

"I wish. She came back early and decided to roller skate through the halls,"

"So that's why she was going so fast," Woo-joo mumbled under his breath.

"Well we haven't seen her,"

"Ah that girl is going to be the cause of all of my hair going gray," Mr Kim sighed, exasperated. "Tell me when you see her," they nod, waiting until the teacher has gone to turn and run up the stairs. Ki-joon burst into the classroom first, chest heaving from how hard he had ran, eyes set firmly on Yuna. She's surrounded by other students, smiling and laughing loudly, Ye-seo holding onto her arm tightly. Woo-joo took her in carefully, able to see her properly now that she's not running.

She's very pretty, with big, brown eyes surrounded by dark lashes and pale pink lips that curve upwards as she chats. Her hair is dyed a shade of pink and curls around her shoulders, messy yet suiting her small face, and dimples appear when she smiled. She has this kind of aura around her, that seems bright and comforting, seeming to be the embodiment of happiness. Woo-joo glanced to his left to find Ki-joon watching her with a gentle smile, arms crossed as he leaned against the wall. Yun looked in his direction, grinning widely and running in their direction.

"Ki-joon!" her voice is deeper than he expected, tinged with a foreign sounding accent, and she pronounces the name with fondness coating every inch of it. He laughed, catching her and hugging her tightly. "Did you miss me?"

"Missed the silence, yes," he answered. "You, not so much," she pouted, hitting him.

"You always say that. But I know you missed me. Seo-joon said you did," Ki-joon's mouth drops open.

"You're my brother, yet you betray me?" his offended voice is drowned out by both of them laughing, Yuna wrapping Seo-joon in a hug, having to reach up to compensate for his height. She switched her gaze to Woo-joo, raising an eyebrow.

"Hwang Woo-joo," he introduced himself.

"The one who moves into Auntie's house?" she offered him a smile. "Nice to meet you. I'm Song Yuna. I hope we get along,"

"My mother came to your house to give you rice cakes, but it was all locked up,"

"Really?" she tilted her head. "That's a different way of greeting then I'm used to. My mom heard about that from Ye-seo's mom. She'll be pleased to meet your mom,"

"The others don't really like my mom," he said.

"I can imagine. Someone coming and challenging the traditions of Sky Castle?" she shakes her head. "It caused quite the uproar. Luckily, my mom doesn't care about stupid things like that,"

"Her mom's scary," Ki-joon whispered theatrically. She rolled her eyes, elbowing him.

"He's right though," she shuddered. "But she's still pretty nice,"

"Yuna-ah!" Ye-seo calls her. "Come here!" she flashed them one last smile before walking over to the girl.

"She's nice," Woo-joo says.

"So you're saying we weren't?"

"Nah," he grins, ducking to avoid Seo-joon's hit.

                                                                              ○

"Unnie!" Ye-bin called out in delight as they walked out of school. "You're back," Yuna smiled widely, hugging the smaller girl back.

"Ye-binnie! How have you been? Cause any chaos while I've been gone?"

"You know it!"

"Soo-han! Come here," he grinned, wrapping his arms around her waist.

"Wow unnie! You haven't grown at all," Yuna's smile went stiff and she smacked his head.

"Yah! How can I grow in just four months?"

"Soo-han did. He's almost as tall as you,"

"You can't just bully me on my first day back!"

"Okay, okay," Seo-joon said placatingly. "Shorty," he ducked to avoid the book she threw in his direction. They all got distracted by the ringing of their phones, glancing at them to see the same message pop up.

"My mom just said that she can't pick me up since she's at a restaurant with Aunt Ara," Ye-seo said.

"Same,"

"We can just walk home then!" all eyes shot to Ye-bin, the girl quietening once she realized what she said. "Oh. I forgot. We can't," Woo-joo looked between all of them.

"Why can't we? Sky Castle isn't that far away,"

"Woo-joo's right," Yuna spoke up. Protests filled the air, but she raised a hand. "Come on guys. I was away for all this time. I missed walking with you all,"

"Are you sure Yuna?' Ye-seo asked, looking over her worriedly. "It hasn't been that long-"

"I'm sure Ye-seo," Yuna cut her off. "I'll get Ki-joon to carry me if anything goes wrong. Okay?" the boy standing beside her straightened up, nodding. "It's gorgeous out today," she sighed, staring up at the bright blue sky, painted over with white clouds. They'd been having rainy days for the past few weeks, but everything was perfect now, a gentle breeze blowing and lifting up the edges of their uniforms. They must've looked odd, a group of high school students chatting at the top of their lungs as they strode through the streets, but Woo-joo was more immersed in how carefree he felt.

"Yuna-ah, if you don't mind me asking, why'd you go to England for so long?" he asked, voice curious.

"Oh just some family business," she waved her hand dismissively. "Dad took us with him because it was something that required our signatures,"

"Did you bring us anything?" Soo-han asked excitedly.

"I brought myself, didn't I?" the smiles disappeared.

"In that case, can we get a refund?" Ki-joon spluttered as she started hitting him with her bag. "I was just joking!" Woo-joo turned around to see the rest of the Sky Castle kids watching them with exasperated looks that told him that this was probably something that happened everyday. The gates of the Sky Castle residence appeared, and Seo-joon smiled.

"Last one there has to buy everyone ice cream from the market!" everyone started racing forwards, and Yuna gaped as she was left behind.

"This is so unfair!" she whined, Ki-joon laughing as he helped her run. Woo-joo looked around him, and noticed that for once, the children of Sky Castle seemed to be relaxed. Even Ye-seo had abandoned the book she had been reading in favor of teasing Yuna, eyes gleaming brightly. He had only been here for a few days, but had always seen them either in the midst of their parents' fights, or being stressed out because of their impending grades. Never did he see them having fun like this. An arm tugged on his own, and he snapped out of his trance, glancing to find Yuna smiling at him.

"Come on Woo-joo. Let's go get ice cream," he nodded, walking into the store with them, and starting to act as the referee for the brawl between Ye-bin and Soo-han for the last watermelon popsicle.
                                                       

~

"Oh Woo-joo!" Lee Soo-im was tending to the numerous plants that filled their house when the front door opened. "You're home. Did you have a good day?"

"Yeah. I met a new student today,"

"Oh really? What's her name,"

"Yuna,"

"As in the Song's daughter?" Soo-im questioned, brushing off the soil that coated her gloves. "What's she like?"

"Completely different from anyone we've met here,"

"Really?"

"Yeah. She seems to have a pretty relaxed take on life, and it's just-" he hesitated, trying to put what he saw earlier into words. "Everyone changed around her," his mother sat down, looking at him in interest. "I've never seen any of the Sky Castle kids do anything but bicker or argue, but they all became different people when Yuna arrived. They were all messing around, and teasing each other like they were such good friends. Ye-seo was even getting along with Ye-bin," he shook his head, smiling. "You met her mom, right? What is the terrifying Song Ara like?"

"Definitely intimidating," Soo-im said, smiling at him as he got up and started making tea for them, bustling around in their kitchen. "She's very elegant, but has this air of humility around her. Everyone was gushing over her son getting into SNU,"

"Ki-joon and Seo-joon were talking about that too. Apparently he's going to be a neurosurgeon too,"

"Her father-in-law owns the hospital your father works at. Ara-ssi's family is very well connected apparently, and she's very proud of her children,"

"Did she mention anything about the family that used to live here?"

"She didn't want to talk about it. Said in very polite terms that Soo-jin had told her about me asking about Myung-joo and that she was good friends with them, but doesn't want any questions,"

"That makes sense. If what Seo-joon has told me is true, the Songs are the center family in Sky Castle,"

"Well I can agree that they are a very important part of this community. Why don't you go and wash up? Your dad'll be home in a while, and we should cook something delicious for him to eat,"