Yachi Haruaki is a high school boy. He has a natural resistance to curses, so his father Honatsu sends him cursed instruments called "Worse" to let him break the curse. One day, Haruaki receives a black cube from Honatsu. That night, he encounters a naked silver-haired girl stealing rice crackers. She is the human form of the black cube, an instrument of torture called "Fear in Cube". Haruaki and the girl 'Fear' fight together against other "Worse" instruments and their owners, using Fear's 32 mechanisms of torture.