When Jo Yang Sun is driven out of house and home after her father is framed for a crime, she is forced to crossdress in order to make ends meet as a bookseller, where she meets Kim Sung Yeol, a handsome, but mysterious scholar who is actually a vampire. Meanwhile, an evil presence at the royal palace stops at nothing to keep the Crown Prince from claiming his rightful throne.

Depicts the love lives, jealousies and desires of those that work within the Sanguiwon during the Joseon Dynasty period. The Sanguiwon are responsible for the attire worn by royalty. Dol-Seok (Han Suk-Kyu) is the best master artisan in charge of royal attire. He views set rules as paramount to his job. Kong-Jin (Ko Soo) is a genius like designer, born with dexterity and an excellent sense. He was brought to the palace by nobleman Pan-Soo (Ma Dong-Seok) who first spotted his talent. The King (Yoo Yeon-Seok) and Queen (Park Shin-Hye) then become embroiled in a critical case because of the royal attire made by Dol-Seok and Kong-Jin.

A story about three friends who just turned twenty; an age where you can do whatever you want, love whoever you want with opportunities abroad.