Miyako, a Japanese woman who was suddenly transported to another world, now lives quietly as an apothecary under the name Mia. One day, on a house call to a brothel, she finds a huge man groveling at the entrance. Apparently, he is on the verge of being banned from the establishment for being far too insatiable.
Mia herself suffers from a troublesome condition caused by the miasma of this world: she absorbs it, but in exchange her sexual urges grow dangerously strong. To keep her raging desires in check, she asks the man to share her bed.
Later, when Mia is summoned to the imperial castle, she spots a familiar face in the audience chamber. The man from the brothel is none other than the holy emperor Ezekiel, ruler of the realm.
This is the comic adaptation of Katsuragi Ataka's novel The Holy Emperor Was Secretly Insatiable. It is a pure but steamy otherworld romantic comedy about a saint who cannot control her desires and an insatiable emperor who earnestly courts her.