Set in 2027, Alfonso Cuar—n’s newest endeavor, “Children of Men,” does not feel like science fiction. Nor does it feel like fiction at all, for that matter. In this glimpse of the future there are no droids, hovercrafts or space suits. Rather, the demise of humanity stems from problems that are anything but far-flung - current issues of government corruption, terrorism and immigration have evolved in the worst way possible. Cuar—n creates a reality that is neither distant nor unbelievable - and that is what makes it so terrifying.