As the number of mincemeat murder victims grows, Shinichi, alone in his knowledge of the truth, is in turmoil. When Migi suddenly alerts him to the presence of another parasyte, he is aghast to find that it is in his own school. Paranoid, Shinichi attends a schoolwide assembly, where the staff introduce a beautiful new teacher...

Shinichi has regained some semblance of a normal life. However, with Migi's cells dispersed throughout his body, his physical abilities have greatly increased to the point that not even Mitsuo poses a threat. Shinichi fears that the changes go beyond the physical and into the psychological. Just as peace returns to his school, 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.

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...