Three sisters, who only have each other and never enough money, get entangled in a conspiracy involving the rich and powerful.

Based on a novel of the same name, it tells the record of a royal court romance between the King of Joseon who believes his duty is to his country first above love, and a court lady who wants to protect the life she has chosen.

The series is about an incident that takes place when the owners of the boarding house called 'Guest Summer Palace', which breaks stereotypes, and boarders with secrets gather to find Lee Seol who disappeared 13 years ago.

It depicts the past of a prominent female forensic investigator suffering from antisocial personality disorder and the process in which the shadow of the father she killed threatens her honor and life.