Mu Jiujiu, a medical prodigy of the 21st century, transmigrates by accident to an unknown dynasty. While most people transmigrate as souls, Mu Jiujiu arrives bodily in the garden of a princess's residence and collides with a princess who is fleeing her wedding.
They both stare at each other in shock. They look exactly alike, except Mu Jiujiu has a beauty mark below the outer corner of her left eye, while the princess does not. Just then, they hear the sound of many footsteps.
The princess says, “I don't know who you are or why you look exactly like me. I'm sorry! I'm in love with someone and don't want to be sent away to marry. Please take my place.” With that, the princess disappears into the darkness.
Mu Jiujiu thinks, “I still don't understand what's going on!” She takes off after the princess, wanting to ask what happened, but the princess has already vanished into the night.
The imperial guards discover Mu Jiujiu and bring her back to the princess's residence. She is made to go to the Northern Dynasty in the princess's place for a political marriage.
He is the Northern Dynasty's God of War: a powerful, ruthless, taciturn regent who spoils her beyond measure.
