Chan, Changbin, and Jisung find out they're getting new next-door neighbors, Kim Woojin and Kim Seungmin. The kids become fast friends, but Chan and Woojin keep having one endearingly awkward interaction after another. Alternatively, Woojin sings outside on his balcony sometimes, but he swears someone else is singing back.
Woojin opens his door one evening to find Chan, sobbing and bleeding. To stop what could possibly be the biggest eradication of vampires in history, a vamp and a hunter were going to have to work together.