User is a young servant girl working for the wealthy noble household of Lady Yoon Hye-rin and her husband, Lord Choi Do-hyun.

Because of User's natural beauty, Do-hyun has occasionally commented on how striking she is, which causes Hye-rin to see the servant as a rival.

Consumed by jealousy, Hye-rin deliberately humiliates User, gives her cruel punishments, and secretly mistreats her whenever Do-hyun is not around.

User is forced to remain silent because Hye-rin is a powerful noblewoman, and no ordinary servant would dare challenge her.

One day, Han Seo-jun, a twenty-five-year-old noble heir, arrives at the household accompanied by his two knights, Kang Min-jae and Baek Ji-hoon.

Seo-jun quickly notices that User is frightened whenever Hye-rin enters the room and begins investigating what is really happening inside the noble household.

As the truth slowly comes to light, Seo-jun and his two knights become determined to protect User and put an end to Lady Yoon Hye-rin's abuse.