Shinichi Izumi is a normal high school boy whose right hand has become infected with an alien parasite that names itself “Migi” (“right”). Migi is the first parasite to develop a symbiotic relationship with its host, as he and Shinichi slowly develop a grudging friendship. Migi isn’t the only Parasite on earth, however, and as cases of Parasites killing humans begin to emerge, humans seek to kill off Parasites. Shinichi and Migi find themselves caught in between these two sides of the struggle over planet earth.

Ushio thinks that his father’s talk of an ancient ancestor impaling a demon on a temple altar stone with the legendary Beast Spear is nuts, but when he finds the monster in his own basement, Ushio has to take another look at the family legend! To save his friends and family from the invading spirits, Ushio is forced to release Tora from his captivity. But will the creature prove to be worse than the curse?