During the late 19th century, Great Britain has become the greatest empire the world has ever known. Hidden within its success, the nation's rigid economic hierarchy dictates the value of one's life solely on status and wealth. To no surprise, the system favors the aristocracy at the top and renders it impossible for the working class to ascend the ranks. William James Moriarty, the second son of the Moriarty household, lives as a regular noble while also being a consultant for the common folk to give them a hand and solve their problems. However, deep inside him lies a desire to destroy the current structure that dominates British society and those who benefit from it. Alongside his brothers Albert and Louis, William will do anything it takes to change the filthy world he lives in—even if blood must be spilled.

Since childhood, Haruka Kotoura's classmates have seen her as a creepy and monstrous person. This is due to her ability to read other people's minds—the same ability that drove her parents away, leaving her alone with her grandfather. As a result, she has grown accustomed to the bitter treatment by the people around her, becoming completely cold and unsociable to others. However, everything starts to change when Haruka transfers to a new school. While most are off put by her as usual, she meets Yoshihisa Manabe, who finds her power astonishing. Yoshihisa then proceeds to befriend Haruka, promising to never leave her no matter what happens. Haruka's new experiences of social belonging thus begin, meeting new friends and learning to open herself along the way.

On the islands of Cremona, a vigilante runs amok. Celebrated by some and hunted by others, the notorious Killer B takes justice into his own hands, armed with a sharp blade and superhuman abilities. Unable to apprehend this renegade, the Royal Investigation Service (RIS) calls upon the expertise of Keith Flick, a seasoned, yet eccentric detective who was relegated to the Archives Department following a personal loss. As crimes in Cremona begin to escalate, from stealthy executions of wrongdoers to sophisticated strikes on public figures, it soon becomes clear that there is more than one person responsible. With the help of his impulsive sidekick Lily Hoshina, and unexpected aid from the elusive Killer B himself, Keith begins to unravel plots involving secret organizations, domestic terrorism, and human experiments. When the involvement of the RIS extends beyond the scope of justice, the extent of the government's corruption—as well as the trustworthiness of close allies—are thrown into question.

Kohachi Inugami, a detective who specializes in the occult, arrives at a remote village in the Japanese countryside, tasked by a hostess at a local inn to investigate a string of incidents involving rotting and mutilated livestock corpses that have been appearing for seemingly no reason. While surveying, Inugami notices a peculiar young boy working in the fields. Evaded by his peers and called Dorotabou for his stench, the young farmhand is surprised that anybody would take an interest in him. Inugami, piqued with curiosity, enlists Dorotabou in helping him with the investigation, despite scorned looks from the villagers. Unbeknownst to Dorotabou, this investigation will reveal a strange new world to him—one of the beast-like entities known as Kemono existing in tandem with humans—along with breathing new purpose into his previously empty life.