Gaimetal, a metallic mineral with high amounts of pure energy, was discovered 50,000 meters underground in 2047, and began mining worldwide. However, Gaist, which are metallic life forms whose bodies are fully embedded with Gaimetal emerged in 2055 and started to attack people. In 2064, Rekka, Hayato, Kurama, and Siren are among those known as Gear Gaist and they faced the battle with more than 100 varieties of creatures Gaist.

A terminally ill girl named Himari Takakura is miraculously saved from death by a strange spirit who resides in a penguin-shaped hat. However, in exchange for extending her life, the spirit tasks Himari's brothers, Kanba and Shōma, to seek out an elusive item known as the Penguin Drum with assistance from a trio of strange penguins.

Kotoko Iwanaga became the god of wisdom to the supernatural beings and spends her days solving problems for them. However, the boy who she fell head over heels for, Kuro Sakuragawa, is someone that is feared by all supernatural creatures. The two of them face various mysterious incidents involving the supernatural in this love x romance x mystery series. Where will these fantastical incidents lead them and what will happen with Kotoko’s crush?