Despite a 200-year-old treaty between humans and vampires, both races still don't get along. Amidst the looming tension, Jung Jae Min, a posh yet kindhearted high school student, quickly falls for the mysterious new girl Baek Ma Ri. But can Ma Ri conceal her true vampire identity and give love an honest chance? If these star-crossed lovers can find the courage to make the leap, Jae Min and Ma Ri may just be the key to a final resolution between humans and vampires...

One day, a stationery store in front of an elementary school is struck by a lightning and a mysterious thing happens.

Set in the constitutional monarchy in an imaginary South Korea, South Korea's Crown Prince Lee Jae Ha is forced to join the World Officers Competition, WOC, by his brother. There, he meets North Korea's strongest female devil instructor Kim Hang Ah.