I saw this was getting a second season after many years, is decently rated on MAL and was on Netflix, so I decided to watch it. Why this is rated highly on here I don't know. The animation is good but that's about it, 2014 must have been quiet.
The story repeats itself each arc: Something is happening in the school, then a load of terrorists attack. These are the most unlucky teenagers ever as they keep getting caught up in terrorist attacks. The police are clearly hopeless as the teenagers have to deal with the terrorists themselves.
The final arc was all over the place, I was too bored to play attention.
The characters are boring, I didn't care about any of them. The brother-sister relationship was really creepy.
Don't waste your time unless you like flat characters with a bit of action.