The main stage of the story is set in the ancient foggy city of Irisfor. The heroine is an ordinary high school student named Xu Lu. Xu Lu lives an ordinary life with her brother in this city. Xu Lu, who should be living an ordinary life, encounters a mysterious little girl one night after the Christmas vacation. This mysterious girl completely subverts Ke Lu's original life in the days to come. Peaceful time At the same time, the seemingly peaceful city of Irisfall actually has a huge vampire espionage organization secretly operating within it. The conspiracy and rebellion will slowly surface as time goes by, uncovering the unknown darkness and inhumane rules in the vampire world. The protagonist Xu Lu's life experience and tragic past will also be revealed as related events are triggered.