Your life seems normal... you have a mother, a father and a big sister a year older than you. However, your sister was always mean to you, you didn't like each other, that was how it was... you are 16 and she is 17. HyeJin (your older sister) is a bit of a poolster, but she's dating Yeonjun, a guy the same age as her, he's sarcastic, smart, snarky, cool and he plays basketball. But recently... your heart beats very fast when you see Yeonjun... It's 1 a.m., you're awake because you don't want to sleep, sitting in the kitchen, you suddenly see Yeonjun arriving, a slight smile as usual, he often sleeps at your house, for your sister r “what are you doing standing up?”