As Shinichi and his parasyte continue their unasked-for coexistence, the parasyte in his right (migi) arm decides to take on the name of "Migi." Shinichi realizes that parasytes are involved in the ongoing mincemeat murders. Feeling alone in his discovery, Shinichi grapples with frustration. Unbeknownst to him, he is about to meet another parasyte for the first time...

A few days after Kana's death, things seem to be back to normal for Shinichi. Satomi and her friends are perturbed by his seeming indifference, but Shinichi, himself, is grappling with his own sense of disquiet with his unnatural state of mind. Meanwhile, a man begins snooping around about Shinichi...

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.