High school student Mizushima receives Valentines Day chocolates from the new student, Monami Arukado Little did Mizushima know that the chocolates contained traces of Monami’s vampire blood. He gets infected from eating them and Monami confesses that she wants to live with him forever as vampires.
Overtaken by jealousy from seeing the two together Mizushima’s girlfriend Keiko Furano teases Monami relentlessly. While attempting to uncover Monami’s greatest weakness, Keiko finds out her true identity as a vampire.
Meanwhile, Mizushima decides that he wants to fully become a vampire with Monami’s help. Keiko sees the two on the school rooftop kissing and in a state of hysteria, attempts to throw Monami off the roof but falls off herself instead.
Keiko dies but her father, Kenji Furano, the mad scientist, resurrects her as Franken girl. Thus begins a deadly combat between Franken Keiko and Vampire Monami in the name of love.