Brief Story Line
An excellent Seoul Criminal Profiler Yoon E-na (Kim Da-mi - Soulmate, Itaewon Class TV series etc) was the witness of her uncle's murder ten years ago and was suspected by the rookie police Kim Han-saem (Son Suk-ku - The Roundup, Big Bet TV series etc), though it was never proven. Because of the trauma that made her lost a bit of her memory, E-na had been seeing psychiatrist Dr. Seong Joo (Park Gyu-young - Sweet Home TV series, Love + Sling etc). In present day, a series of gruesome murders started where the killer left a piece of puzzle to E-na related to each of the crime.