Plot

17-year-old Shinichi Izumi is partially infected by a Parasyte, monsters that butcher and consume humans. He must learn to co-exist with the creature if he is to survive both the life of a Parasyte and a human as part monster, part person.

The 16-year-old Izumi Shinichi lives with his mother and father in a quiet neighborhood in Tokyo. One night, worm-like aliens called Parasytes invade Earth, taking over the brains of human hosts by entering through their ears or noses. One Parasyte attempts to crawl into Shinichi's ear while he sleeps, but fails since he is wearing headphones, and enters his body by burrowing into his arm instead, taking over his right hand and is named Migi. Because Shinichi was able to prevent Migi from traveling further up into his brain, both beings retain their separate intellect and personality. As the duo encounter other Parasytes, they capitalize on their strange situation and gradually form a strong bond, working together to survive. This gives them an edge in battling other Parasytes, who frequently attack the pair upon realization that Shinichi's human brain is still intact. Shinichi feels compelled to fight other Parasytes, who devour humans as food, while enlisting Migi's help.

They arrived in silence and darkness, descending from the skies with a hunger for human flesh. Parasytes - alien creatures who must invade and take control of a human host to survive - have come to earth. No one knows the secret except high school student, Shinichi Izumi, who's right hand has been invaded by a Parasyte. Shinichi and Migi, the Parasyte, begrudgingly form a friendship in the middle of a silent war between humanity and the Parasytes.—Wessel Pot

While worm-like aliens called Parasytes invade Earth, one of the aliens fail to crawl into a boy's ear. This Parasyte burrows into his arm instead where Izumi Shinichi is forced to live with it. The two form a strong bond to work together to survive.—Boclan Twothousand