Being a vampire, hepato-pancreato-biliary - specialized doctor Park Ji-sang tries hard to suppresses his thirst for blood to treat ill patients and save lives. Ji-sang finds himself falling for his colleague in Taemin Cancer Hospital: Yoo Ri-ta, a hotshot physician who is the niece of the chaebol group chairman who owns the hospital. He also gets drawn into a conflict between good and evil as he encounters Lee Jae-wook, a two-faced hospital chief who gains everyone's trust with his gentle demeanor, but inwardly harbors a dangerous ambition for power and a talent for cruelty.