Set to a small town just after nuclear bombs wipe out most of the big cities of the US, the show is a show about survival, human comradeship and how easily lives can change.
What makes Jericho so good is how authentic it is. You can basically feel the panic of the population of Jericho about their situation, you can see them make irrational choices and, when they end up at war with another city, you see the confusion and the shock that this is actually happening to them. They really do seem like ordinary people thrown into extreme situations (with the exception of Hawkins, who might be a bit unrealistic character-wise). You have people who've never fired a gun in their life standing guard and mentally preparing themselves to kill people if they are attacked. It seems real, it seems believable. You can relate. That is the strength of this show, in addition to a good plot. I just finished season 1 and am very sad the second season only has 8 episodes. Also, some plot lines just end. But it makes sense in this situation. Suddenly, a character dies in the middle of their plot line. That's what happens in circumstances such as this. That strengthens the show aswell, and makes it even worse to see beloved characters go.
The dynamic between the two Green brothers is almost worth the show alone, but I watch it for all the characters. They all have strenghts and flaws, they do stupid things that make you want to yell at them and they don't always think ahead. Just like everyone else.
You should watch this show! It is one of the best shows I have ever come across.