Park Sunyoung and Lee Jinki have been together since the day they were born. They were both born at the same hospital, on the same floor, on the same day, and at the same hour. The following reveals their time as children. 

1994

Lee Eun Hye caressed a beautiful baby in her arms and smiled. Her husband, Lee Jin Sang, held her arm protectively and gazed at his son.

"He's so breathtaking. I hope he'll grow up to be a studious man." Lee Eun Hye sighed.

"What should his name be?" Lee Jin Sang asked his wife.

"You know what it is. Lee Jinki, a precious foundation. I want him to be someone you can always rely on." Lee Eun Hye said carefully. She nodded to herself proud of her explanation.

"Whatever you say, yeobo. Lee Jinki. What a lovely name. Welcome to this world, my boy." Jin Sang held his son in his arms.

"How is Yoo Jung doing?" Eun Hye questioned.

"I do not know. Here, I'll put Jinki in the crib. I don't want to tire either of you. Let me call Il Sung." Jin Sang said.

~~~

Park Yoo Jung chuckled at the bitter look on her daughter. "Aigoo, my child. Already you're showing anger at your mother."

"Yoo Jung-ah, what shall be her name?" Park Il Sung asked.

"I haven't given it all that much thought." Yoo Jung pondered for a while, until she gasped.

"Yoo Jung, are you alright?" Il Sung exclaimed.

"Of course. I have a name. Park Sunyoung. What do you think? She'll grow up to he a woman with only goodness inside, just like her name. However, we'll register her name as Luna Park for when we go to America, it will be easier."

"Yes. That is perfect. I love that name. Park Sunyoung, welcome." Il Sung smiled.

"I wonder how Eun Hye is doing. Can you call Jin Sang?" Yoo Jung asked.

"Actually, Jin Sang is calling me right now. I'll be back. Be careful." Il Sung said, stepping out of the room.

"Yeobo seyo?"

"Il Sung-ah, has your wife given birth yet?" Jin Sang's voice showed eagerness.

"Yes. Has yours?"

"Yes! It's a boy. His name is Lee Jinki. He was born at 9:35 pm. I bet yours is a girl, right?"

"Wah, such a nice name. You're right. It is a girl. Her name is Park Sunyoung and her English name is Luna Park. She was born at 9:37!"

"That's a beautiful name. And, wow! Thats amazing! Our children were born within minutes of each other. This is truly luck for us. Who knew this would happen? Well, I have to hang up because Eun Hye needs something." Jin Sang said. Il Sung heard the voice a crying child in the background.

"Okay. Bye. Take care of Lee Jinki and Eun Hye and of yourself."

Il Sang hung up.

~~~

2000

A young girl pushed another young boy on a swing. The boy was jubilant, kicking his legs back and forth. The girl had an indignant look on her face, not a hint of a smile on her face.

"Yah, Lee Jinki! I'm tired." The girl complained, giving Lee Jinki another jostle

"Sunyoung-ah, that's what you get for losing! I told you that our fathers met in their high school days." Jinki smirked.

"How was I supposed to know that? I don't even know what high school is!" Sunyoung said, flustered.

"That's your problem. You shouldn't have argued with me then!" Jinki said.

"Stop acting like you're so smart!" Sunyoung shouted. Fed up with Jinki,Sunyoung leaves the swing and goes inside.

"Sunyoung! Wait! I want to play!" Jinki called after her. He jumped off the swings and rushed inside to see four suitcases standing in front of him.

His eyes lit up. "Umma, are we going on a trip?"

Lee Eun Hye looked at her son and chuckled. "No, we are not. Jinki-ah, Sunyoung is moving to America. She won't be coming back."

Jinki's face turned into stone. "Sunyoung is leaving?" He saw Sunyoung sitting on the couch gloomily. He ran to his room and came back, clutching something. He sat next to her and smiled.

"Sunyoung-ah! This is for you!" Jinki held out a green child-size ring.

"I don't want it." Sunyoung looked away. Jinki held the ring out in front of her and she looked up and gasped.

"Lee Jinki! I have the same one!" Sunyoung took out an identical ring, but a white color.

"Here, this is for you." Jinki put the ring on her finger.

"And this will be for you." Sunyoung imitated Jinki. Jinki smiled and ruffled Sunyoung's hair.

"Stop it!" Sunyoung moved back.

"Sunyoung! Jinki! Please come here!" Park Yoo Jung called.

"Say goodbye to each other." Eun Hye said.

"No. I want Lee Jinki to come with me!" Sunyoung said.

"Sunyoung-ah, Jinki will come later. We're just going first. You like being first!" Yoo Jung knelt down.

"No! I don't like being first! I want Lee Jinki!" Sunyoung cried.

Jinki watched her helplessly. He suddenly got an idea.

"Sunyoung-ah, I have a secret to tell you!" Jinki called her over. Sunyoung eagerly went to Jinki and listened.

"Sunyoung-ah, I'll come to America after you. I still have to buy a robot for you, remember?" Jinki said.

"Okay! Annyeong Lee Jinki!" Sunyoung said, hugging him.

Jinki wiped away tears and hugged her back. He watched her leave morosely and sighed. He couldn't do anything when his best friend was leaving.

"It's alright, Jinki. Sunyoung will be back." Eun Hye clutched her son's shoulder comfortingly.

~~~

2014

"Jinki-ah, Park Sunyoung is coming." Lee Eun Hye told her 20 year-old son.

"Umma! I am Onew now! And, what? Park Sunyoung is coming? She's my childhood enemy!" Onew exclaimed.

"Lee Jinki, do not say that. You loved playing with Luna when you were little." Eun Hye said.

"Umma, I was little then. When she came to visit us when I was nine, she was such a brat. She's annoying!"

"People change." Eun Hye said, leaving his side. "Anyway, only Luna is coming and she'll be going to your university from now on."

Onew grumbled, going back to his room. He would make sure Luna would obey him. He would not allow her to boss him around like how she did when they were young. 

Author's Note:

Hi everyone! 

I've decided to gift you all with a few moments of Onew's and Luna's past! They were cute children, weren't they? 

I hope you enjoyed this chapter :) 

Bye bye!