The plot in a nutshell is very simple: a dead childhood friend from the main protagonists past returns to haunt him (not in creepy way) and the group reunites to find the thing the girl needs in order to be able to move on. AnoHana is about this group of friends, their relations to one another, the guilt and other feelings the death of their shared friend has aroused in them.
The main element in AnoHana in tragedy, and how different people perceive it and react to it. This anime is on a mission to make you cry. Despite the supernatural element (the ghost of the dead girl, Menma) the characters in AnoHana are very carefully planned and appear to be as wide scale of personalities as possible and, even more importantly, none of them is the perfect Mary Sue. If you haven't watched the series (or even if you have) take an extra assignment: whom of the characters you resesemble the most?
As AnoHana drills into the feelings and personalities of it's characters, there is not really room for anything else in the 11 episodes. You could say AnoHana is about people rather than things or events. Each scene aims to create a strong emotional impact be it nostalgia, joy or sadness. This is both a strength and a weakness: on one hand the series can be a very powerful emotional experience, on the other hand some of us may feel that there is very important elements missing. AnoHana has nothing you could chew and process in your thoughts. Like a soup or a game with low replay value, you experience it and then it's gone. I can't see myself watching AnoHana again. I cried for it once, a second round would hardly bring anything new to it.
I believe this to be an anime that divides opinions. If you are a fan of drama and tragedy, watch it. If you prefer a traditional shounen format of saving the word or protecting friends, you probably don't get too much out of this. It's a matter of genre, and perhaps a bit of stepping aside for stereotypical genre formats. AnoHana about small, insignificant people and their insifnigant lives. Personally, I think that exactly is brilliant.
