Will Sun-hee be able to defeat the rivals around her and succeed in her sweet kiss with Jin-so? There is one sweet proposal for such a good girl, and that is the first kiss with Jin-su! Sun-hee is a fresh-faced college girl who always dreams of a romantic kiss with her first love. Jun-seok, an innocent young man who just has to do the same volunteer work and look at it from the side... A chance first kiss with Sun-hee, I achieved it for that moment, but it was just a small contact accident. It's hard to be completely confident in Sun-hee, who only considers herself as a younger brother and a junior. That's the nursery school where your first love is the essence. Sun-hee, who had participated in all kinds of community service activities for her father, had one volunteer project that she went to just for herself. "I love you Sun-hee..." She is gentle and always warm, and she rushes to see him. Can his first love with Sun-hee come true?