Narumi Katou is a middle-aged man afflicted by the strange ZONAPHA Syndrome, an uncommon and baffling illness that forces its sufferers to experience intense seizures unpredictably, with the sole remedy being to witness another's laughter, in the midst of his daily grind. During a routine shift at his part‑time job, Narumi encounters a young boy carrying an enormous suitcase who is fleeing from three men. The boy introduces himself as Masaru Saiga, the newly appointed head of the renowned Saiga Enterprises after his father's recent demise. Yet other relatives plot to murder him and seize the inheritance for their own benefit. Resolute to protect the youngster, Narumi aids Masaru in escaping and confronts the assailants, only to learn they are sentient humanoid marionettes endowed with superhuman power. Just as Narumi faces defeat, a white‑haired girl bursts into the battle and quickly calls forth another puppet from Masaru's suitcase, proclaiming herself Shirogane, his guardian. Karakuri Circus tracks the intertwined destinies of three strangers from varied walks of life as they uncover an age‑old saga of affection, treachery, and the everlasting protracted clash between mankind and automatons for generations.
