Shinichi Izumi is a typical high school boy whose right hand is now infected by an alien parasite which names itself"Migi" ("right"). Migi may be your first parasite as Shinichi or she he slowly create into a friendship to create a relationship with its own host. Migi isn't the sole Parasite on ground and humans seek to kill Parasites off, as examples of Parasites killing humans start to emerge. Migi and shinichi find themselves caught between these two sides of their struggle over planet earth.