Long time ago in ancient Japan, human beings could still see Yokai monsters and were afraid of them. However, as time passed and civilization and enlightenment progressed, people started forgetting about them... Though a son of the leader of all Yokai monsters, Mikoshi Nyudo, an adorable looking monster, Tofu Boy, has no talent in scaring the human beings. He is always scolded by his father and laughed at by his monster friends. One day, he decides to go on a journey to find out about the meaning of his life as a Yokai monster and to see his mother he's never met before.