An implant was developed to combat a deadly virus, which was then implanted into the nervous system of humans. Regrettably, unscrupulous individuals exploited this implant technology to create blood-red eyed creatures referred to as "Roido," which serve as human weapons. The defense agency established the Karakuri unit to confront this threat, with human members monitored by small talking animals. During his leave, Kiru the karakuri visits his friends Koten and Koron, only to discover that there are no breaks in the fight against the Roido!
