Kyuta, a boy living in Shibuya, and Kumatetsu, a lonesome beast from Jutengai, an imaginary world. One day, Kyuta forays into the imaginary world and, as he's looking for his way back, meets Kumatetsu who becomes his spirit guide. That encounter leads them to many adventures.
Humanity is suffering from a series of mysterious murders across the globe, known as the 'Mincemeat murders'. High school student Izumi Shinichi has a parasite living off him, having replaced his right hand, and he might be the discoverer of truth.
Humanity is under attack by human-mimicking flesh-eating alien parasites. One parasite bonds with his young high school student host, and he convinces the parasite to help him stop the others.
