In town, blood-sucking incidents are growing frequent. As Kitaro investigates, he receives a letter. The sender wants to be killed. Kitaro goes to visit the sender and meets Onozaki, a genetics researcher. Onozaki has created immortal cells and conducted an experiment where he injected himself with them. As a result, he has obtained an immortal body and also turned into a youkai. When he transformed into a youkai, he lost control and went seeking blood. All the recent blood-sucking incidents were Onozaki`s doing. Because of the immortal cells, Onozaki can`t kill himself, so he begs Kitaro to kill him, but...