Yuuki Reiko, member of the Occult Club, barges into the Sket-dan's room holding a picture of one of Kaimei Academy's seven mysteries, the "Ghost of the Incinerator". The Sket-dan are on the case (mainly Switch), trying to find out the truth behind the picture, and getting Shimada Takako from the Newspaper Club mixed up in it, too...
Ooh, looky here! The almighty Onihime's 
actually got a cute side to her!
¡Quién lo hubiese imaginado!
¡Quién lo hubiese imaginado!
Oh, olha só! A poderosa Onihime 
tem um lado meigo também!