Rin Shigure, a lonely high school girl who lost her family at a young age, lives a harsh life — mistreated at the orphanage and shunned at school. Even so, she clings to the hope of one day reuniting with her long-lost “big brother,” whom she was separated from eight years ago. However, her bleak everyday life is turned upside down when she encounters a mysterious youkai. “I’ve finally found you — my servant.” This “reunion” with Shuten, the legendary oni who once plunged the ancient capital of Kyoto into fear, marks the beginning of a twisted, obsessive journey through a bizarre otherworld — one filled with Rin’s overwhelming devotion and maddening love.