Death end re;Quest 2

After killing her abusive father and being decided that it was in self defense, Mai a young gloomy girl is sent to a women dormitory called “Wardsworth” in the city of Liz Shoala. There she hopes to find her lost sister and her reason to live Sanae. But soon her hopes are crushed by reality, not only does she not find her but also it seems that she was never there to begin with and nobody knows about her existence. That's when she mets Ninomiya Shiina and her story begins...