There's an anime I had watched on tv at least 8 years ago and ive had it in my head from time to time trying to figure out exactly what it was. I will explain it to the best of my knowledge in hope of someone knowing what it was called. The movie consisted of a group of high school kids who were at school at night for some reason and the world was about to end, I think they may have even been the last people alive on earth but thats just a guess. Anyway I remember it having good characters and some good dialogue so I guess thats why I still remember it, I know I didnt give much info on it but I hope it helps.