After their hometown was destroyed, childhood companions Kafka Hibino and Mina Ashiro vowed to become officers in the Defense Force—a militarized body charged with shielding Japan from gigantic monsters called "kaijuu." Their bond, forged in shared dreams and the loss of their community, strengthened their resolve. Years later, the 32‑year‑old Kafka has nearly abandoned his heroic aspirations. He now spends his days clearing the wreckage left by defeated kaijuu, while Mina has already fulfilled their shared ambition.
When he meets his new colleague Reno Ichikawa, Kafka confronts a reflection of the ambitious youth he once was: someone who yearned to serve in the Defense Force. Soon, the pair encounter a rogue kaijuu. Kafka displays his natural bravery and saves Reno from imminent death, but the ordeal leaves him severely wounded.
During their recovery in a hospital, Kafka is attacked again by another beast. The assault grants him the power to transform into a humanoid kaijuu, inheriting the strength and abilities of Japan"s colossal monsters. The army labels him "Kaijuu No. 8," and he vows to wield his new gifts for the greater good. United by respect, Kafka and Reno join forces with warriors like Mina to stand at the front lines of the Defense Force. They pledge to protect every citizen, hoping their sacrifices inspire a new generation of defenders together.
