In the not-so-distant future, a man-made catastrophic event has devastated a large region of Japan, forever changing the lives of its people. In the years since the incident, the Japan Ground Self-Defense Force has genetically engineered humans to operate under the lethal conditions of the contaminated city. Today, three such humans set foot into the now forsaken city. The trio of girls are known as Coppelion, trained since birth to use all of their skills and resources to carry out their one and only objective: to rescue those left behind.