Transported to an unknown era, Subin, a teenage girl raised with western values, wakes up in the body of a serf. In this unknown land, she encounters the aristocratic Kim brothers and finds herself entangled in the webs of deceit; woven by rivalry, politics and hunger for power.

"But sir," I say desperately, "I'm not even Korean. How can I go and do an undercover job?" When Mirei, a rookie reporter, is sent to go undercover as a housekeeper for a popular K-pop boy band, she is determined not to have anything to do with them. Not to mention that she is an avid fan of their rivals, BTS. What will Mirei do when she realises that there was more to the EXO members than they seem? And what will EXO do when it is time for her to leave?