Masaya Kakei is a university student, but he attends a school that's not his ideal school. His days are generally gloomy. One day, he receives a letter from serial killer Yamato Haimura, who was convicted for eight murders and received the death penalty. Back when Yamato was committing his murders, he ran a bakery store. At that time, Masaya was a middle school student and a customer at his bakery store. According to the letter, Yamato confessed to committing the murders, but he insists that he did not commit the last murder. Masaya begins to investigate the last murder case involving Yamato.

Shuhei’s erratic mother feels threatened when he starts to awaken to a world beyond her distorted control, sending the family hurtling towards tragedy.

Alien pods come to Earth and, naturally, start taking over Human Hosts. One such pod only manages to take over one human's, Shin Izumi, right arm. Together they grow and co-exist, all the while the other aliens are making meals of other humans; Shin feels he must put a stop to it all, but his alien, Migi, doesn't see why.