In the 16th century, the Onin Rebellion broke out in Japan, and the war spread across the country in an instant. Domestic conquests continued, and the people were displaced. At that time, demons and evil spirits took advantage of the situation and wreaked havoc on the world. Vampires, led by the demon king Guiyuan Zhenzu, slaughtered living beings wantonly. In contrast, another part of the vampire hunters stepped forward to fight against this group of demons, fighting each other for nearly 400 years. In the 1970s, the hunter group existed in the name of "Red Shield", and the girl hunter Fujimoto Xiaoye (played by Jeon Ji-hyun) among them was particularly outstanding. Xiaoye is a girl born from the combination of vampires and humans. On the surface, she is an ordinary 16-year-old female high school student, but in fact she is a vampire hunter nearly 400 years old. She was ordered to sneak into an American school in the U.S. military base, where she met the general's daughter Alice (played by Allison Miller) and rescued her from the hands of the vampire. Zhenzu and his men are ready to move, and the grievances between them and the hunters that have lasted for hundreds of years are finally going to be settled...