A violent confrontation with a gang brings Shinichi face-to-face with a girl named Kana, who begins to take an interest in him. Shinichi's parents continue their vacation, but their trip is cut short by an unexpected attack.

Shinichi sets out for revenge and runs into an unexpected ally. Together they team up to take down the Parasyte that brutally attacked Shinichi's family. But when Migi falls asleep, Shinichi is forced to engage the enemy on his own.