In a regional city in the present day, Sayaka Mimuro manages her family's Shinto shrine on behalf of her absent parents. Along with her childhood friend Haru and a talking furball (rabbit?) god, she lives a peaceful life, but when an earthquake strikes, yokai suddenly appear and her world is torn apart.

Sayaka receives divine news that the only one who can save the city is herself—she is actually an onmyoji with the power to vanquish yokai on her own! However, in order to unlock her powers, she must first perform sex rituals with a man...

"...If I'm the only one who can do it, then I guess I have no choice!"

Sayaka is bewildered to say the least, but her natural sense of justice gives her the resolve to fight...

"There is only one person I can ask to do this and that's you, Haru... Please?"

With no one else to turn to, Sayaka asks a confused Haru to be her partner in the sexual rituals. With Haru's help, Sayaka finally unlocks her battle-princess powers to wage war on the yokai that ravage her city...

[From Shiravune English page]