Renowned for being the country with the highest number of kaiju appearances, Japan is often subjected to fatal monster attacks, making it vulnerable. To counteract these threats, Japan has established the Defense Force, whose primary objective is to disarm kaiju. Kafka Hibino, who has dreamed of becoming a member of the force since childhood, is responsible for disposing of kaiju carcasses. However, his aspirations take an unexpected turn when he undergoes an unforeseen transformation. Given that he has turned into a kaiju, the question remains: How will he fight against them?