In their separate worlds, two beings lead opposing lives, disconnected and solitary. Ren had experienced kindness from only one person, who was tragically murdered, and as a result, he was shunned by the rest of his family. He has no choice but to seek refuge in the streets and alleys of Shibuya, where he crosses paths with Kumatetsu, a formidable beast who introduces him to the magical world of Shibuten. Kumatetsu sees in Ren a chance to prove his worthiness as the next lord of the realm, despite his martial prowess, the beast lacks both disciples and a way to showcase his abilities. Opposing goals notwithstanding, they agree to aid each other in achieving their respective objectives. While Kumatetsu desires recognition, Ren, now Kyuuta, is searching for a home. As time passes, they come to the realization that they are assisting each other in more ways than they had initially envisioned, and the gap between boy and beast might not be as wide as they thought.