The Crossed series is about people trying to survive in a world where a virus has turned most of humanity into the Crossed. What sets the Crossed apart from zombies is that they retain human intelligence and speech, and possess a very sadistic streak - leading to the graphic displays of violence and gore that has made the series notorious.
There is no overarching story - the Crossed arcs all focus on different characters, and the creative team varies from story to story.
The best I've read from the Crossed series was the webcomic,
which you can check out here. You should probably give it a shot, see if you like it, and if so, you'd probably enjoy the other Crossed books as well.