The elite military unit, the Defense Corps, protects civilians from the kaiju that have been appearing all over Japan for many years. The remains of the monsters are cleaned by professional cleaners, one of whom is Kafka Hibino. Kafka is dissatisfied with his job, as he had wanted to join the Defense Corps since he was a teenager, but his attempts have been unsuccessful. However, he gets a chance to fulfill his dream when a parasite enters his body, granting him the ability to transform into a kaiju.