I just started watching this show today, and for now it has been really interesting. The first episode is an introduction to the characters, how they were before and how they are now. The story develops around 3 main characters, 3 "so called sisters", who all are vampires and try to adapt to the modern life.
Han Yi Na, the middle sister, owns a clothing shop, she then decides to open a SNS account (Instagram I think) and gains 1 million followers a day. There are articles all over the Internet about her gaining that many followers in such a short time notice.
The episode ends here.
On a production note, the sound is so good? It sounds really cripsy and you can really hear all the details going on (walking on concrete, heels...). The video quality is really nice. The production budget seems really high for a drama that you can watch on Youtube!
I will write another review when more episodes are released :)