Kaiju are giant monsters that have been terrorizing Japan for years. A special unit fights them, while another group cleans up the remnants of battles with giant beasts. Kafka Hibino is currently working on disposing of monster remains. In the past, Kafka wanted to become a member of a unit fighting Kaiju, but he failed. Unexpectedly, Kafka interacts with a Kaiju-parasite that causes him to turn into a monster. With the help of his younger colleague Reno Ichikawa, Kafka hides his identity while striving to fulfill his lifelong dream of passing the Defense Force exam. And when a mysterious intelligent Kaiju attacks the Defense Force base, Kafka faces a crucial decision in a desperate situation...