More than two centuries have passed since Japan was devastated by nuclear war. Cut off from the world, the island is now a place of terror and mysteries: wonders of science some believe best forgotten, monuments to a bygone era of human decadence, and irradiated monsters ready to tear apart any humans foolish enough to set foot there. After being wrenched from his family and falsely convicted, a French soldier of fortune named Leon finds himself on a cargo plane to Japan. He and his fellow convicts are given one year to locate a powerful weapon from ages past—a weapon known only by the codename TORATSUGUMI—in exchange for their freedom. But what is the true nature of this weapon, and how is it connected to the taloned, half-human girl who swoops in to save Leon?