Shinichi's life returns to "normal" after A's killing spree, but Shinichi remains in low spirits. His mother, Nobuko, becomes worried, but Shinichi just bluffs when she asks him what's wrong. His father, Kazuyuki, suggests to Nobuko that a past incident may be involved. Nobuko looks down at the old scar on her hand and thinks back to what happened when Shinichi was a little boy...

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.

Kana's special ability is gaining in strength. Believing that ignoring her will only endanger her life, Shinichi tells Kana everything about the parasites. Shinichi only wants to save Kana, but Kana believes Shinichi is lying to her. They are two ships, passing in the night...

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...

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...

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?