Kim Sunggyu have two sisters, one biological older sister while the younger one is not exactly his sister since his mother bring her to their home one day. Mrs Kim said to her children that Jieun won't be lonely and Sunggyu won't be the youngest since they have a new member in the family. Jung Eunji. Mrs Kim thought it will be awkward for her children to be around with Eunji on the first day but they prove her wrong when Eunji and Jieun get along very well.

That night, after dinner, Mrs Kim asks Sunggyu to bring Eunji to her bedroom. While Sunggyu leads Eunji to the bedroom, Mrs Kim tells the whole story to Jieun. Mrs Kim seems to be holding her tears so much while telling Jieun the story. Jieun hugs her and pats her back. A silent sobbing sound can be heard. One can feel the atmosphere is pretty gloomy even by looking at them.

Back to Sunggyu, he feels slightly awkward with Eunji when there is just the two of them. Sunggyu also does not talk much with Eunji. He just don't know what to talk about. Even when it is just being alone with his noona, they mostly stay in silent, doing their own work, but the silent is comfortable. This silent he have with Eunji is going to take months to get to that level. Sunggyu opens the bedroom door and tugs Eunji into bed. He feels his cheeks burning when he suddenly making an eye contact with Eunji. When Sunggyu gets up from the bed, he can feel a hand holding his wrist.

"Sunggyu oppa, can you stay for a minute? I need someone..."

Sunggyu hesitates for awhile before he can see tears in Eunji's eyes. Sunggyu nods. He sits down at the bedside while waiting for Eunji to speak up her mind. He feels some kind of electric shock when Eunji hugs him. Sunggyu just sits there, not knowing what to do. His mind goes blank. Then, he feels warmth at his chest. He looks down to see Eunji is silently crying her heart out. Sunggyu hugs her back and her hair caringly.

"I will protect you, Eunji, no matter what."

12 years later...

Kim Jieun is in lead for being KimOne's heir. KimOne is a family company which have been going on successfully for over decades. It started out from her great grandfather, going down to her grandfather and her father. Now, it's her turn. Everyone approves the idea of having her as the next heir because of her leadership and charismatic personality. She is now preparing herself in improving her qualities and skills while Sunggyu is in college and Eunji is in her senior year.

The bond between the three of them is getting stronger after their mother's death two years ago. Jieun, being the eldest, she have to stay strong for her siblings. She is now in charge of providing bright futures for them. Sunggyu and Eunji are her motivation to keep on living her life after her mother's death. It is pretty hard to act strong when she is not but whenever she feels down and weak, she will always shares her pain with Eunji.

One night, Jieun and Eunji finally having a heart-to-heart talk for the first time they have been living together.

Jieun eonni, I admire you so much, you can't even imagine how much I admire you.

What do you mean, Eunji-ah? You're so random sometimes.

I'm being honest here, eonni. You don't even hesitate to accept me in your family.

Well, Jung Eunji, to be very honest with you, I do hesitate, but after hearing what Mom told me that night changes me.

What did Mom told you, eonni?

Are you sure you're gonna be okay?

Yes I am, eonni. You're the one teaching me to be strong. Jieun ruffles Eunji's hair causing Eunji to pout.

Mom told me that your parents' relationship wasn't going well. The day before that night, your mother told Mom to take care of you for awhile since she feels that is not safe for you to be with her. She said that your father had some anger issues or something like that.

Yeah, my father is like that. And when my mother caught him cheating on her, they fought. They fought really bad.

I know... I'm sorry Eunji-ah. I'm sorry about your mother too.

That's okay eonni, I have you now. I have Sunggyu oppa too. You guys are my family.

Yes Eunji-ah, you have us now. We have each other.

Eonni, somehow I can't trust guys because of my father. Is it bad? It is bad, isn't it? Eunji can't contain her tears anymore. Jieun quickly wipes her tears and hugs her. They both stay like that, being oblivious that someone is actually eavesdropping the whole conversation.

**********

A few minutes later, Jieun gets a text from Sunggyu, saying that he is currently waiting for them downstairs to have dinner together. 

Eunji, that is not bad at all and it's not your fault, okay? Besides, you trust Sunggyu more than other guys around you and that is a small step for you to trust other people in the future. Come, Sunggyu is waiting for us downstairs.

Really? He didn't tell me...

He texted me just now. He really should have told us earlier though.

Since he starts to live in hostel, we rarely have dinner together. I miss the three of us together, eonni.

Me too. Now, let's go. Sunggyu is waiting.

Sunggyu is setting up the table for dinner. He buys japanese food since the restaurant is just a stone's throw away from his hostel. He sees Jieun and Eunji walking down the stairs. He smiles at them. Soon, the three of them sit down and eat their dinner, talking about their routine. Sunggyu listens to every stories his sisters tell him, but somehow he seems distant. He can't help his own curiosity about what he heard earlier but he just keep it to himself. He knows the whole story since Jieun tell him but he never bring the topic up whenever he is with Eunji. His eyesmile does not seem genuine during the dinner.

**********

After the dinner, Sunggyu and Eunji both clean up the table while Jieun is taking a call from her assistant. Most probably about the company. Eunji breaks the silence between them.

Oppa, can you come to my graduation day? Jieun eonni can't come because she have an important meeting on that day.

Oh your graduation day? When is it?

Next friday oppa.

Shouldn't you guys have a senior night or some sort of party before the graduation day?

I'm not going oppa.

Why not?

I don't feel comfortable. I don't even know much about boys at my school.

Then, what about your girl friends?

They have dates. I don't.

Knowing you Ji, you probably reject all of those boys who have been asking you out.

Yeah... I only feel comfortable with you, oppa. Sunggyu stops doing the dishes for a moment before continue doing it back.

Oh oppa, I also apply for your college. We will be going to the same college oppa. We will see each other more often. Isn't that great? Sunggyu can hear the excitement in Eunji's voice.

That's wonderful Ji, but you're not going to live in the hostel right? Who's going to stay with Jieun eonni then?

Hmmm I'll talk to eonni about that. Sunggyu puts away the last cup before grabbing his car keys, phone and wallet. Eunji pouts.

Do you really have to go tonight, oppa? Can you stay?

I'm sorry, Ji. I really have to go. I'll text you and Jieun eonni, don't worry.

Okay. Oppa, don't forget to come to my graduation day!

Yes, I will. Say goodnight to Jieun eonni for me, Ji. Sunggyu waves at Eunji before closing the door. The sound of a car driving away from their house can be heard. Eunji smiles. How can Sunggyu alone makes her feel so happy in many different ways?

The Graduation Day...

Parents start to fill the seats in front of the stage early in the morning. The ceremony is held at an outdoor garden near the school. Sunggyu takes his seat among the audience while talking to Jieun on the phone. Eunji, on the other side, is searching for Sunggyu among the crowd. Her heart starts to beat faster than usual when she can't find Sunggyu. I need him. I need Sunggyu, thought Eunji. She grabs her sleeves nervously.

Chorong pokes Eunji's side, signaling her that she does not have to worry since Sunggyu will definitely be here. Eunji feels a hand snake around her waist, she quickly turns around to see who is the owner. Bomi, while showing her pouty lips, is backhugging Eunji. I saw Sunggyu oppa earlier, don't worry Ji..., says Bomi. Eunji seems to be relaxed after that. The teacher is making sure that the students are lining according to the name list. The ceremony must go on smoothly. It is an important day for every students after all.

The ceremony starts with the speech from the principal followed by giving the certificate and graduation slip to the students. The weather is very peaceful and a little windy, suits the happy atmosphere. The ceremony ends after the student representative gives the final speech before they all cheer and throw their graduation cap. Each and every students starts to find their parents and family members after that. Eunji searches for Sunggyu in the crowd. She then stops when she sees Sunggyu in front of her in a very far distance, holding a bouquet of flowers like he is going to propose her.

Sunggyu oppa. I can't find you in the crowd earlier.

That's okay, I have the perfect view of you from my seat. Here. 

He gives the bouquet to Eunji. She accepts the bouqeut delightfully and smiles to him genuinely. She is so happy whenever Sunggyu is with her. She doesn't even know why but she doubt herself sometimes. She knows she have a feeling for Sunggyu more than just an oppa but she probably having it in one-sidedly. Even though Eunji and Sunggyu treat each other like brothers and sisters but of course, it is possible for one to fall in love with the other since they're not real siblings.

Eunji knows that she can't trust guys but with Sunggyu, it feels different. It feels like he is the only she can trust and without him, she is lost. When Eunji seems to be caught up in her own thoughts, Sunggyu smiles and leaves her behind. A minute after, Eunji tries to catch up to him. Eunji sees Sunggyu's hand on his left side while the right one is in his pocket. The urge to hold his hand is huge and uncontrollable. She walks slower than Sunggyu to take her chance of holding his hand from the back. 

Just when she wants to hold his hand, Sunggyu stops, resulting her head to bump into Sunggyu's shoulder.

Ji, did you hear what I just said?

Sorry oppa, I didn't. What is it again? she rubs her head spontaneously even when it doesn't hurt at all.

That's okay. Sunggyu starts to walk towards his car, probably sulking.

Oppa, don't be mad at me. I'm sorry okay? Eunji finally slips her hands into his and intertwines their fingers together. Sunggyu can't help but stops on his track. He can't look at Eunji at the moment. He is trying to differentiate his own dream from the present.

I'm sorry, oppa. I'm sorry for making you uncomfortable but---

Ji, is it true that you can't trust any guys other than me?, Sunggyu ask without looking at her.

Y-Yes. You're the only one and I don't even know why, oppa.

Then I hope that this is mutual. Sunggyu turns around. Hands are still intertwine. His eyes are looking at Eunji's in a foreign way. Eunji never knows that this kind of loving stare from Sunggyu would actually exist for her. She is sinking deeper in his eyes.

Jieun eonni is going to be very happy to hear about us. You never know how long I've waited for this day to come, Ji. Sunggyu let go of Eunji's hand to take off Eunji's graduation cap and slides her bangs aside. He leans in and leave a kiss on her forehead before he leaves Eunji startled.