Couldn't find a thread on this.
It's another one of Cormac McCarthy's novels (No Country for Old Men), and the book was fantastic. If this movie is done like NCfOM, then it will be spectacular.
Basically, the world ends and there is no explanation. The entire book is just a man and his kid trying to survive. There is no vegetation, just remnants of what humans had created. They are constantly moving, because there are roving bands of cannibals and vagrants who have no issue with eating/killing/raping them. The landscape is barren and the atmosphere is cold, the only sense of warmth coming from shoddy fires and the man and his son, who are never named.
There are some pretty gruesome scenes in the book, and it was utterly compelling. I've read a few of McCarthy's novels, and they're all disturbing and disgustingly intriguing. I will definitely go see this movie.