Elara Nova, an Earth girl who constantly had weird nightmares and could see ghosts, was working in a library in Sphinere Castle. Kairos Dimension, who claimed to be an interstellar personal detective, came to Earth in a cargo spaceship and detected abnormal fluctuations of electromagnetic waves in this very castle, so he decided to investigate. They met in the library at midnight and discussed the possible source of those electromagnetic waves, including a notorious legend involving a devil imprisoned underneath the castle by the Gods. However, a secret book owned by the curator of the library indicated another story.