Chae-yeon, who has never been in a relationship, secretly has a crush on Nam-gyoo, the president of her company, and practices kissing in front of the mirror every day. One day, Chae-yeon musters up her courage and asks Nam-gyoo to kiss her, but Nam-gyoo avoids her, promising her next time. But in fact, Nam-gyoo has never kissed properly before, so he goes to take kissing lessons to fulfill Chae-yeon's request.