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...
You woke me up with your RAIN message!
Why are you so mad?
!أيقظتني برسالة رين خاصتك
لماذا أنت غاضبة؟
Deine LEIN-Nachricht hat mich mitten in der Nacht
geweckt, brauchst also nicht sauer sein!
No te enojes después de 
despertarme con tus mensajes.
No te enfades después de
despertarme con tus mensajes.
C’est ton message qui m’a réveillée,
alors ne t’énerve pas !
Non hai motivo di arrabbiarti, visto che mi hai buttata 
giù dal letto a notte fonda con un messaggio, no?
Você me acordou com suas mensagens
do RAIN! Por que está tão furiosa?
Разбудила меня сообщением! 
Кто ещё злиться должен?