Splash Splash Love (TV Miniseries)

Danbi is a senior high school student taking the College Scholastic Ability Test (CSAT). However she has an irrational fear of maths, and in order to escape taking the test travels through a time portal to the Joseon era. In Joseon she is mistaken for a eunuch and serving in the palace becomes a confidante of King Lee Do. Danbi finds that in the Joseon Dynasty her high school level of maths and science makes her the greatest scientist in the entire Kingdom, falling in love with the King she inspires him in his reform of the country. However, fearing for their own privileges, Danbi becomes the target of traditionalist courtiers who seek her death. Having a hand in saving both the King and the Queen, Danbi becomes friends with the Queen who, in order to allow the King and Danbi to be together, endorses Danbi becoming a royal concubine. Presented to the Queen Dowager, who is a doppleganger of her own mother, Danbi becomes very home sick and taking her leave of the King returns to the present day. Returning to the exact moment of her departure, Danbi becomes determined to sit the CSAT, having learnt in her sojourn in Joseon that problems are not solved by running away, but by facing them.