Kurotori Chiyoko, a 5th-grader in elementary school, loves the occult. One day, a friend requests her to do a love fortune-telling. Chiyoko tries to summon Cupid, but thanks to a stuffy nose, accidentally summons a witch named Gyubid instead!
From that day on, Chiyoko starts learning witchcraft from Gyubid, the self-proclaimed hottest instructor of the magic world. The training regimen is tough, and punishment for slacking is harsh. Fortunately, Chiyoko is able to keep her extra-curricular studies secret, aided by the fact that no one else can see Gyubid.
Alternative Titles: Kuromajo-san ga Tooru!!, Kuromajyo-san ga Toru!!, 黒魔女さんが通る!!