They rom when night falls and everything is dark, those who catch their attention are doomed to their fate, unlucky, police call the cases V.S.A, short for Vampire Serial Attack, to prevent copy cat cases they hide one certain detail every case leaves, the victim's all were left with no blood not a drop, one fate filled night San a 16 year old high school student with a incredibly smart mind and intuition like no other was attacked by a Vampire leaving him between life and death at the last second was saved by a private detective named Yoon who was asked to investigate the cases of V.S.A, San amazingly survives the attack but at a cost of not being human anymore, now with his new powers and Yoon he must survive the new world and solve the mysteries and catch the one who made him that way.