Hanbok wearing Kwon Oh Jung and Heo Young Ran are not good at lying or studying. But Ui-chan is good at studying, Jeong-bae is naive, and seminars are children who always go together to see her behave like a heavenly girl. However, under the water, only the children are stained as if black water pollutes clean water, and Mi Sun sheds tears. Due to the special feature, Oh Jung has time left for a week, and he decides to make a date and a promise that he hasn't dated. For a week, she can't meet other people because of her promise to Young-ran. (Source: SBS)