Do Kyungsoo awoke one winter night and felt the sensation of moisture on his chest; his clothes were drenched in sweat. It was 3 am and when he approached his bathroom mirror, he noticed he was pale and felt an insatiable thirst that was unquenchable by water. Only blood could fill that thirst. Through the course of several nights, he discovered he became a vampire. Now he fights his inherent urge for blood while also fighting a sect of Vampires who indulge in their desires. Kai, his childhoo

After the death of his wife, Nayeon, Sungkyu's life becomes hell. 2 years after her death he attempts suiciding, but fails and find himself face to face with Woohyun, a former classmate whose prank introduced Sungkyu to Nayeon in the first place. Soon enough the two find themselves in a war against fallen angels, where Sungkyu takes on the form of a monster in order to seal them in hell. At the end, despite beginning his life anew with Mina (former classmate as well), Sungkyu is forced to dea