After the events of "Minazuki-tan 2 ~Demons' Gate~", the demon gate has been unleashed,
and the fourth shogun has revived the 3 remaining others.
As the demon gate above the city disappears from view, a sense of unease lingers.
Minazuki and co. try to investigate, but don't seem to be getting anywhere.
Just then, an unexplainable event occurs...