First some items I need to adress. I'm Dutch to expect some spelling errors, if they are to annoying just message me and I'll fix it.
My opinion may vary from others and this is fine. People are different so there is a good chance that I will not like what you love. Deal with it. I'm not telling you that you should hate it too, I'm telling you why I didn't like it.
I'll try to keep swearing to a minimum but fail utterly on occasion. In general it is the more the anime pisses me off the more I swear so watch out for the low scored ones.
Art: Art is fine as it should be for a modern anime. There is not much to say about this, it's fine.
Sound: No real complaints actually, it's pretty ok. Voice actors are good and I don't remember any music either. This is how I generally prefer my anime.
Characters: The main characters are 9 and 12. Their real names are unknown but they are highly intelligent and very focused on getting revenge. 9 is cold and calculating while 12 is much more happy go lucky.
Lisa is a young highschool girl who runs into the boys. Her mother is smothering her and she is bullied at school.
Shibazaki is a police officer whos carrier was sidetracked after crossing the wrong people. He is very intelligent and latches onto the terrorist case.
Story. Lisa's live is Hell. Her mother smothers her and she is bullied at school. All this changes when she runs in 9 and 12 during a terrorist attack. She discovers that they are the terrorists and decides to join them. While not happy with the attacks she is interested in the boys and their goal.
Rant. The anime starts pretty strong with the boys stealing weapons grade plutonium before moving on to their next phase. The boys are very intelligent and manage to plan everything down to the second to carry out their plan. It is very unfortunate though that the crashing building is very similar to the collapse of the WTC during 9/11.
Sadly the anime takes a nosedive when 5 turns up with the US government. Why? Because up until then it was more or less based on reality. 9 and 12 planned everything perfectly and people played right into them. 5, however seems to know everything. Including the things she shouldn't or couldn't know. It is almost that she is psychic in how she handles things and it pulled me out of the series.