At first glance, Ibara Naruse and her friends Aoi Fukasaku and Taeko Nomura appear to be ordinary, carefree high school students. However, the streets they traverse, their destination, and their surroundings are far from normal. As they press on, the trio finds itself venturing deeper into an uninhabitable version of Tokyo, a city ravaged by a nuclear disaster twenty years prior. As members of the Dispatch 3rd Special Force Coppelion, known as the Health Care team, Ibara, Aoi, and Taeko are backed by the Japanese Ground Self-Defense Force (JGSDF) and Colonel Onihei Mishima while they search the eerily silent streets for survivors. Locating the last remaining humans and having them evacuated by JGSDF helicopters is a daily routine for the girls. Yet, as their work continues, Ibara and her friends begin to question their own humanity—specifically, how they are able to survive in Tokyo without any protective gear.