When Arima Seigen is transferred to Asahikawa Penitentiary, he thinks he understands the rules of survival. But Asahikawa isn't just a prison. Beneath its surface, an intricate hierarchy of power thrives, where the pecking order is decided by bloodshed and only the ruthless survive. That being said, Seigen's plan is simple: survive. Do whatever it takes.

His plan, however, starts to unravel the moment he meets his cellmate, Jikuin. Rumors say he's the most dangerous inmate there, with so much blood on his hands, he's more myth than man. With a past shrouded in violence, Jikuin's able to navigate the chaos with unsettling ease, and Seigen can't help but be drawn to the dark safety of his mysterious orbit.

Though, as Seigen grows closer to Jikuin, he begins to question whether trusting him is a step towards safety - or a dangerous gamble that might drag him into a nightmare of his own making. In a place where survival means trusting no one, the line between ally and threat grows increasingly blurred.