Sixteen-year-old Shinichi Izumi retains control of his mind after an alien parasite fails to reach his brain and instead settles in his right hand. The creature, named Migi, cannot move elsewhere and depends on the high school student to survive. Neither can escape their uneasy coexistence, and hostile parasites regard the pair as a threat to their species that must be eliminated.
Shinichi’s predicament is part of a sudden alien invasion of Earth. Other parasites burrow into human brains, seize complete control of their hosts and alter their forms to feed on unsuspecting victims. With Migi confined to his hand rather than controlling his brain, Shinichi faces a different fate: defending himself alongside the alien that tried to take him over.
