A short haired girl bumped onto Arin, they both lost their balance and fell. The girl looks like she was running away from someone or something. It's Arin's first day on this school and she might be in trouble, she knows, she already knew when she saw the teacher running towards their direction. It looks like the teacher have been chasing the girl for quite some time. Arin was about to speak when the teacher told them to go on principal's office. Arin sighed and didn't even bother to speak, it's a waste of energy, she thought. She doesn't even bother to listen on what the principal is saying. But then, when the short haired girl talked, Arin thought that the girl's voice is cool and calming. The girl explained why she was trying to cut class, it was her parents who will be out of the country for two months because of their business, she wants to say goodbye properly. After the girl finished explaining the principal's eyes went on Arin. "And you, what's your name again?" asked the principal. "Arin, it's Arin, ma'am." She replied calmly. "Why are you here?" The principal's brows furrowed. "We accidentally bumped each other and the teacher thought I was with her or at least trying to help her." After hearing the girls' side, the principal let go of them. Although, the short haired was given a punishment for what she did. Arin let a heavy sigh as she got our from the principal's room. Before Arin said a word, the short haired talked. "Yoobin, but you can call me Binnie. I'm sorry for the mess I've caused. I want at least to apologize properly, meet me tomorrow, after school." Without any words from Arin, Binnie left. And from that day, the two of them gotten closer.

"Let's make a promise, if you finally reached 20 and the both of us aren't dating someone, we will date each other." Binnie said while looking at Arin's eyes, Arin thought it was silly but she still agreed. For some reasons, she wants to make it happen. Since elementary, they both know each other, they saw each other's worst and best. Why not try this kind of bet, right? Few years later, when they turn into college, of course, both girls and boys tried hit Arin up. At lunch, when the two of them sitting on the side, minding their own business, a person stood beside them. "Hey, can I sit with you, guys? The canteen is full and it's really hard to find a table." Binnie said yes and smiled at the girl. "My name is Jiho, Kim Jiho." the girl said with a wide smile on her face. The three of them were chatting when someone called Jiho and sat at the three's table. "Hey Nyang!!! You didn't mention you have new pretty friends!!!" The girl keeps shouting, although they are only sit apart. "If you don't mind, Seunghee. Can you please lower your voice? We just met, and I guess we're already friends?" Jiho sighed.

Arin's head is full of thoughts, she still thinks about the promise they made years ago. She didn't date anyone the past few years, she's not really into dating and there are some things she want to prioritize, that what she thinks. Some things changes since they went to college, Binnie isn't visiting Arin's place every weekend. That's just new to Arin. Thinking about the promise, she also thinks how Binnie made her feel safe. How gentle the girl is, how she cared for her. How simple words become magical when it's Binnie whose saying those. Such as "I think you're really pretty", the words Arin always hear, but when it was Binnie who said those, she felt butterflies. The girl is clueless about her feelings but deep down she knows that she wants to be kept by Binnie forever, to be on her arms, while crying or laughing.

One more day before Arin's birthday. She's enthusiast and putting a lot of effort in everything she does. This time she isn't denying her feelings anymore, she's planning to confess on her best friend tomorrow. And with a hope on her eyes, she hope Binnie will remember the promise they made back then. It's already eight on the evening, Binnie, Arin, Jiho and Seunghee made a plan about going out because they know, Arin will be busy for the party tomorrow. Arin doesn't really pay attention on her face, she doesn't put make up, but today, it's quite different. She puts a light make-up to highlight her features. The four of them started chit chatting when Binnie told everyone to pay attention on her for she has an announcement to make. Arin's heart beat became faster, thinking it's about the promise. But then, the words came out om Binnie's words were far from her expectations. "Jiho, the prettiest person I've ever know. Jiho and I are finally dating." Those words killed Arin softly, but then, she managed to say a word. "I am happy, I am happy for the both of you." trying to hold back her tears, wishing it was her, wishing that it was her name instead of Jiho's.