With Gotou's defeat, Shinichi's life is finally back to "normal." Though saddened by Migi's sudden departure, Shinichi moves forward with his life. However, a final threat appears...
With no chance to survive, Shinichi pulls off a desperate move.
Motivated by Satomi to stay alive, Shinichi resolves to fight Gotou. With Migi's support, they press their attack in an isolated forest. However, they fail to finish Gotou at a critical juncture, causing Shinichi to lose Migi and flee in defeat.
The assault squad succeeds in eliminating Hirokawa, the parasites' leader, but they find themselves in a bind when the ultimate parasite appears. Their failure to eliminate Gotou strikes fear into Shinichi's heart--who will give him the final courage to face Gotou?
The joint operation by the police and the strike force to eliminate the group of parasites led by Hirokawa has begun. Yamagishi's unit uses their special sensor system to hunt down the parasites. Amidst the chaos, human victory seems all but confirmed. But the tables are about to be turned by a single parasite...
Shinichi and Migi arrive at the park, only to find Tamura holding her child. As Shinichi struggles to quell his fury at the sight of her, Tamura unleashes a flurry of questions about the meaning of the parasites' existence and what humanity means to them.
Having determined Tamura to be a threat, Kusano's group moves to eliminate her. Meanwhile, Kuramori moves to avenge his family's death by abducting Tamura's baby. With her baby in his arms, Kuramori faces Tamura and threatens to throw the infant down a steep slope--what will Tamura do?
The newest parasite to appear is different from the others. Chatty and expressive, the parasite identifies himself as Miki and immediately makes his move. With Migi asleep, all Shinichi can do is to run and keep running...
Though still full of doubt, Kuramori has, for the time being, accepted Shinichi. Soon after, Kuramori's resolve is severely shaken by witnessing a parasite murder a human being. Shinichi is frustrated by the turn of events, but the lull is cut short when a new parasite appears...
Shinichi's secret becomes known to Kuramori, the private investigator hired by Tamura. Shinichi tries to confide in Satomi, but his unsuccessful attempt only drives a wedge between them. Shinichi recruits Uda's help to break the impasse.
Incapable of rationala thought, Shimada Hideo is a savage beast on a rampage, and Satomi's class has become his prey. Shinichi must make his way through the carnage in order to save Satomi...
Yuko is drawn to Shimada Hideo, but gradually realizes that something is seriously amiss with Shimada's face itself. As Yuko pursues Shimada's secret, she connects the dots between him and her brother's police investigation.
Thinking he'd found his mother's killer, Shinichi instead meets Uda Mamoru, a man in a similar situation as himself. Uda sympathizes with Shinichi and suggests that they all work together. The time to avenge his mother has come at last! Shinichi heads to the precipice...
A species of parasitic aliens descends on Earth and quickly infiltrates humanity by entering the brains of vulnerable targets; insatiable beings that gain total control of their host and are capable of transforming themselves to feed on unsuspecting prey. High school student Shinichi Izumi falls victim to one of these parasites, but the creature fails to take over his brain and ends up in his right hand.