In the movie Parasyte: Part 1, a high school student named Shinichi Izumi becomes the host of a parasitic alien creature that takes over his right hand. The alien, named Migi, forms a symbiotic relationship with Shinichi and gives him superhuman abilities. Together, they must navigate a world in which shape-shifting aliens are secretly taking over human bodies and orchestrating an alien invasion. As Shinichi tries to protect himself and those around him, he finds himself drawn into a police investigation into these alien parasites. With the help of Migi, Shinichi fights against the invading aliens and tries to maintain his humanity in the face of a gruesome and terrifying situation.

In Parasyte: Part 2, the alien parasite invasion continues as the high school student, Shinichi Izumi, and his parasite hand, Migi, are caught in a battle between humans and parasites. With the fate of humanity at stake, Shinichi must face the ultimate showdown against the powerful parasites.