Trump Omoi, a singer who meets Mizuki by chance, learns of the existence of a sinister child named Kitaro. One night, Nezumi-otoko plants the seeds of a vampire tree in Omoi. Omoi's frightened body gradually turns into a tree.

Kitaro insults the Water God, who is worshipped as a deity. The Water God follows Kitaro to Tokyo and throws modern society into panic. Furthermore, since the Water God is "water," Kitaro doesn't know where he is hiding. He is helpless.