In a world plagued by threatening creatures known as Kaiju, Kafka Hibino aspired to enlist in the Japan Defense Force with his childhood friend, Mina Ashiroto, to defeat them. Over time, life circumstances forced them to go their separate ways and caused him to abandon his lifelong ambition. He now finds himself employed by Monster Sweeper, Inc., a professional cleaning company that specializes in cleaning up the aftermath of Kaiju battles while Mina Ashiro is now the Captain of the Defense Force's 3rd Division. After crossing paths with the highly motivated Reno Ichikawa, Kafka's ambition of standing next to Mina as they protect humanity from Kaiju together is reawakened.
