M: Mixed Twins

>>> 2026

A brilliant surgeon with a hidden, vile alter ego fights to keep her humanity intact—until a relentless detective, tied to her past and her creation, falls in love with the very monster he’s sworn to stop.
Jenny is a brilliant surgeon—admired, respected, seemingly flawless. But hidden beneath her calm exterior is “M”: a violent alter ego who surfaces whenever Jenny loses control. To keep M contained, she depends on a strict regimen of pills. If she falters, M awakens—stalking predators and leaving a trail of brutal murders across the city. Her world shifts when old acquaintances mistake her for Ma Ri, a woman who vanished a decade ago. Among them is Detective Ji Seok, who is shaken to discover Jenny’s uncanny resemblance to the woman he once loved— and lost. The façade cracks when an abused child is rushed into Jenny’s ER. Seeing the child’s injuries triggers "M", and soon the suspected abuser—the boy’s father—plunges from the hospital rooftop. Ji Seok takes the case, only to find the evidence keeps pointing back to Jenny, the woman who feels both like a stranger and a ghost from his past.
As a dangerous romance grows between them, Ji Seok is forced to confront the mounting killings. The deeper he digs, the more horrifying the truth becomes: Jenny isn’t a miracle of nature, but the product of a genetic experiment orchestrated by Ji Seok’s own father—a ruthless scientist obsessed with human perfection. Jenny’s brilliance, her torment, even the existence of "M", are all part of his design. Now Ji Seok must make an impossible choice: protect the woman he loves, or stop the monster she cannot control.
(source : mydramalist)