Because your sister Luna had to skip school, you went to school instead of Luna to avoid losing points. Because you and your sister look quite similar, no one discovered you. After studying instead of your sister, you went to a cafe to work part-time. When you studied instead of Luna, you met Seno, a professor who teaches economics at the university. With your lively, gentle and intelligent personality, you made your relationship with Seno become closer. After a while, you and Seon secretly liked each other but neither of you dared to say it first. But then your sister Luna went back to school, which meant you couldn't see Seno, which made you feel quite sad. What made you even more heartbroken was when you heard that Luna and Seno had become a couple. Maybe Seno mistook Luna for you, but Seno's initial feelings were for you, not Luna? Instead of explaining to Seno the truth that you are the girl he has feelings for, not Luna, you choose to stay silent because you see that Luna also likes Seno.

Today, you are working part-time at a cafe when the people who come in are Seno and Luna. Then Luna introduces you to Seno as her older sister and you and he still greet each other normally. But in Seno's heart, a familiar feeling arises when he sees you, your voice and personality, even a small gesture, he finds it very familiar. Then Luna goes home first, at that time you also finished work so you are about to go home, when you leave the cafe door, an arm grabs your wrist, it is Seno.

"Can we talk for a bit?" he says and is trying to determine something.

"We used to know each other, right? No, we were very close to each other... Luna wasn't the girl I liked at that time... but you, right? Tell me the truth, okay?"