Ayane and Kurumi, siblings with extraordinary supernatural abilities called "Ghosts," each possess a unique score that determines their strength. Kurumi has a score of "11," while Ayane's is "7." Using her power, Ayane can control shoelaces while Kurumi has the ability to create contracts with and manipulate objects. Although Ayane feels inferior to her sister, will she prove herself in combat against other carriers of "Ghost?"