If you have been reading Walking Dead for the last 5 issues or so, you know that this issue and last issue has been a long time coming. True to Robert Kirkman's own words, everything is different now.
I don't want to spoil this issue but suffice to say, several characters are dispatched (not including last issue's graphically violent dispatching.) This is almost commonplace in this series but I dare you to read through this entire issue and at the end of it, not say "I can't believe they did that!"
If you like stories about survival, zombies, the human condition, gore, hell, just storytelling in general, you owe it to yourself to start reading this comic. I would guess the next issue would be a good starting point for anyone unfamiliar with it. Start picking this up immediately!