Following an unfortunate accident, Kouta Shibaki, a completely normal heterosexual high school student, is labeled as the school pervert. With girls avoiding him like the plague, the young man's worst nightmare has truly come to fruition. One day in the school library, he comes across a peculiar book said to possess the power to summon witches. Partly out of desperation and partly out of boredom, Kouta decides to play along with the joke of a book, until an apprentice witch named Rurumo Maji Mojiruka appears before him. In an unusual turn of events, Kouta ends up helping Rurumo with some general witchery tasks in exchange for his soul being spared. Majimoji Rurumo follows the misadventures of Rurumo as she attempts to persuade Kouta to use 666 magical wish-granting tickets in her efforts to become a fully-fledged witch, unaware that every time she grants a wish, Kouta's life is shortened. Aided by Rurumo's familiar Chiro, Kouta must decide between helping Rurumo or saving his own life.