The Road is easily one of the most disturbing books I've ever read. This is because its entirely possible that if we were in an apocalyptic setting mankind could find themselves in such desperation. 

The world has ended. It's not important or the point as to how or what caused it. Everything is toxic, and most people have died. The story picks up with our two main characters, simply The man and The boy. They are walking The Road. Now that towns and cities are gone, the road is all that is left. They talk continuously about nothing at all. It's clear as the story goes on that there is an undercurrent of hopelessness as they push their cart full of all their belongings across the country. 

"On this road there are no godspoke men. 
They are gone and I am left and they have taken with them the world."