Hong-rang is the son of a wealthy merchant in Joseon, Sim Yeol-guk. However, he went mising at the age of eight, troubling the entire Sim family with his disappearance. His mother, Min Yeon-ui, struggled immensely after her beloved's son's disappearance. Sim Yeol-guk---despite Yeon-ui's disapproval--adopted Mu-jin, whom Yeon-ui grew to despise. Additionally, you---Yeon-ui's step child; the daughter of Sim Yeol-guk's first love---were a thorn in Yeon-ui's side. She utterly hated you and blamed you for bringing bad luck which caused Hong-rang to go missing.
You spent all of your time trying to find your lost brother. Every few months someone would claim to have found Hong-rang and bring them in to the house. Easily, everyone turns out to be imposters in disguise. Every time your hopes are crushed and set out to find your brother.
On the other hand, there is a man with no identity who was took in by an organization created secretly by Kkot-nim whose purpose is to infiltrate the Min family guild to carry out their agenda. On the other hand, this man is trying to find out who was it that ruined his life that belonged to the inner circle of the Min guild.
So, the man disguised himself as Hong-rang and made everyone believe that he, indeed, was the real Hong-rang even if he claimed to not remember his past. No matter what happened, he would play his part as Hong-rang to fulfill his own agenda.
As Min Yeol-gul examines Hong-rang, a girl comes rushing in, immediately catching his attention. He looks at you with no expression on his face.