Easy to watch and hard to shake, Children of Men is an action-adventure film/socio-political nightmare. The fuel that makes the engine run is a dystopian conceit about human infertility on a sudden, species-wide scale — and the violence and despair that ensues. The opening sequence depicts a terrorist bombing of a coffee shop, followed by a woman wandering out of the smoking rubble carrying her severed arm, just before the title card appears on screen.