Kafka Hibino longs to join Japan's Anti-Kaiju Defense Force, hoping to fulfill a childhood promise with Mina Ashiro. A parasitic creature takes up residence in his body, granting him the power to transform into Kaiju No. 8—the combination of monstrous strength and a retained human mind. He escapes custody and enters the Defense Force to fight alongside Mina and new teammates, all while concealing his altered identity and confronting a rising threat and a deeper mystery behind the outbreaks.

Kafka Hibino longs to join Japan's Anti-Kaiju Defense Force, hoping to fulfill a childhood promise with Mina Ashiro. A parasitic creature takes up residence in his body, granting him the power to transform into Kaiju No. 8—the combination of monstrous strength and a retained human mind. He escapes custody and enters the Defense Force to fight alongside Mina and new teammates, all while concealing his altered identity and confronting a rising threat and a deeper mystery behind the outbreaks.