Dan Bi, a senior in high school who gave up on mathematics, runs away to the Joseon era on the day of SAT. And the very day that determines her whole life, when her life is at stake, someone enters her life with love. In Joseon, she witnesses and experiences that the agony she feels has been continued throughout history, and it isn\u2019t just hers but that of everyone. In that process, she feels comforted and consoled. This story is here to cheer up and comfort those who are striving hard to survive in the hectic and competitive modern day.