Police Lieutenant Cho (Suk-kyu Han) finds his career is in serious trouble: a maverick brought up on charges of police corruption, he's only a heartbeat – or one mistake – away from losing his career. However, a brutal murder pulls him back from the brink, but the circumstances turn even more bizarre than he originally expected: the head, arms, and legs of the dismembered body don’t match up, only meaning that there are far more victims – measured only by the carnage – out there waiting to be found. The body has been dissected with uncanny surgical precision. The department immediately reinstates Cho because of his experience: he’s the only detective with the expertise to head such a dangerous investigation.
As it turns out, all of the victims are former lovers of a reclusive artist, Chae Su-Yeon (played with poised subtlety by Eun-ha Shim). Cho is certain that not only are her remaining friends in danger but also she stands the greatest risk to fall prey to the predator, and now he must race against time to uncover the secret of her past in order to unravel the mystery of their mutual present ... and, possibly, her future.