Seulgi is an assassin for hire, whom one day recieved an assignment to kill a chaebeol named Bae Joohyun. Seulgi may be a cold blooded killer, but what she doesn't know is that, Bae Joohyun herself is a psychopath.

Or alternatively; Joohyun secretly sent the order for her own demise, clearly enjoying the chase of one Kang Seulgi trying to kill her every night. In her words, she is a fan.