A mysterious and brutal attack has decimated the world's population, forcing a small group of survivors to stay alive long enough to unlock the mystery that could save them all.A mysterious and brutal attack has decimated the world's population, forcing a small group of survivors to stay alive long enough to unlock the mystery that could save them all.A mysterious and brutal attack has decimated the world's population, forcing a small group of survivors to stay alive long enough to unlock the mystery that could save them all.