This summer, Lithia, the princess of the divine world, became lovers with Raito, something she had dreamed of since childhood.
However, she is immersed in a melancholy mood after experiencing autumn in the human world, wondering about her and Raito's future. She thoughtfully considered polygamy instead of traditional monogamy.
"I know what Raito and I need the most now... and that's a concubine!"
Without telling Raito, Lithia's search for a concubine begins!
In the meantime, a mysterious airplane suddenly appears on the Verbena Academy grounds!
"Raito-kun's father, maybe he's alive...?"
The sudden appearance of the plane and the amnesiac girl as the passenger will trigger a series of events.
The enchanting journey begins at Verbena Academy in autumn...!