"We’re like siblings, aren’t we?" Cha Seungjo, a soccer player known by everyone in Korea, and Lee Seohui, who grew up in the same house with him like siblings. At 18, Seungjo confessed his feelings to Seohui, and after that, he never returned to Haeyoung, where Seohui was. Six full years passed like that. "I held back until I succeeded, until I became a real adult." "Six years is enough. Don’t tell me to wait any longer, Seohui." When Cha Seungjo came back as a grown man, he was no longer the 18-year-old boy. Maybe that’s why… Seohui felt her heart race in a way she hadn’t six years ago. "Just for ten days, let’s date." Now, Seohui decides to make a choice about her relationship with Seungjo: to keep living like siblings, to act like strangers, or to become lovers.