Yujeong, who works as a night shift nurse at a general hospital's cardiology department, is now told that her 12th-grade younger sister, Kijeong, has been arrested by the police as a suspect in an infant abandonment case. Only then does Yujeong start to make desperate efforts to rescue her sister.

该剧改编自同名网络漫画《亲爱的 X》，讲述国内顶级女演员白雅珍的没落，以及她人后隐藏的双重面孔故事，这是一部通过记录片来追踪反社会人格女演员隐藏的过去。