Kouta Shibaki, a fully normal heterosexual high school student, gets labeled as the school pervert after an unfortunate mishap. With girls avoiding Kouta like the plague, the young man's biggest dread has finally come true! He comes across a strange book in the school library one day that is claimed to have the power to summon witches. Kouta chooses to play along with the farce of a book, partly out of desperation, partially out of boredom, until an apprentice witch named Rurumo Maji Mojiruka comes before him. Kouta, in a strange turn of events, finds up assisting Rurumo with general witchery work in exchange for his soul being saved. Majimoji Rurumo chronicles Rurumo's escapades as she tries to persuade Kouta.