When the end of the world comes, the country requires every household to recommend a person to form a militia to resist the various terrible disasters brought about by the end of the world. Although Yang Ying, who had not been favored by her family since she was a child, was the first to be pushed into the sea of fire, her twin sister Yang Ying was loved like a princess because of the so-called 'Mark of God' birthmark. Struggling on the edge of life and death, wandering between light and darkness. What kind of cruel reality could make her give up everything and be willing to trade her body for weapons in exchange for the right to survive? One is desperate, the other is condescending. See how vulnerability can become strong in desperate situations...