It won the third Seiun Award in 1972,[1] and was the first major work to popularize Hanmura in the world of Japanese science fiction literature.

The novel rewrites the mythology of vampires and werewolves, positing that such creatures are garbled references to a race of immortality seeking "secret masters" who have existed since ancient times.

These "secret masters" are infected with a virus transmitted through sexual intercourse, which instills in them a vampiric craving for blood.

The end stage of the disease puts the victim in a chrysalis state, who then awakens after several centuries as a newly formed immortal.

The story concerns many dramatic intrigues among the wealthy modern individuals who seek to acquire the infection and ensure protection for themselves during the long chrysalis period.