Hisashi Seki, ordinary working guy, wakes up one morning to find a naked, and very amorous, girl in his bed. He's happy to take advantage of the situation, to their mutual satisfaction. However, the girl's appearance leads to all sorts of increasingly strange phenomenon. The cause lies, sort of, in Jungian psychology. The girl, whom he has named Asami, is from a parallel dimension where people's ideal partners - the anima to their animus, or vice versa - reside. Asami's longing has allowed her to cross dimensions to be with Seki, but her presence in his world upsets the natural order. She goes back, and Seki must venture to her world to save her. The lovers are reunited. However, matters don't turn out quite as they hoped.

The story is set in Nagasaki prefecture in Minami Shimabara city, the fabled origin of the Shimabara Rebellion that sent shockwaves through all of Japan in the early Edo period. It is also where a third-year junior high school student named Shirou spends his days with his school friends. One summer day, Shirou's older childhood friend Akane returns to Minami Shimabara from Tokyo. Shirou and Akane take a stroll around Minami Shimabara with another longtime friend, Tokiya. While these friends are dealing with nostalgia and more complex feelings, a mysterious creature named Goron suddenly appears before them. This encounter with a mere little creature causes great events to unfold once more in this city...

After overcoming numerous tribulations, the members of Roselia promised to appear on FUTURE WORLD FES. It is now Autumn... Through writing the lyrics of "Promise," Lisa has matured. Watching the change of color in the autumn leaves, Yukina and Sayo expressed their resolve in a picture letter to their future selves. Driven by the wish to do something for Roselia, Rinko has started to compose a new song. "The remaining quests are the contest, the tournament, and FUTURE WORLD FES..." Reflecting on their goals, Ako starts to feel anxious.

The beautiful Jeanne marries a man named Jean, and the happy newlyweds make their way to the Lord's castle with a cow's worth of money for his blessings. However, the demonic Lord is unmoved by their offering, ignoring their desperate, impoverished pleas. The Lord's wife offers an alternative: Jeanne must become the Lord's conquest for the night in a ritual deflowering. Scarred by the experience, the shaken Jeanne receives no sympathy from her husband. Instead, she is neglected. But as Jeanne drifts off to sleep, she is met by a strange spirit that encourages her to deliver retribution to those who wronged her. And with a mysterious surge of pleasure and an unquenching libido, Jeanne agrees. Kanashimi no Belladonna is a captivating, psychosexual adventure that tells a story of cunning witchcraft and deceitful superstition in a poor, rural village of medieval France.