How an assassin and a Magical girl survived the zombie apocalypse

(Gakkou gurashi/ Assassination classroom/ Madoka Magica crossover)
Sooooooo, Takaoka is back. He escaped. And, of course, the first thing he does is go after Nagisa and try to get rid of him. He tried to kill him, but he accidentally sent Nagisa to another dimension when trying to kill him. Now Nagisa is stuck in a zombie apocalypse trying to survive alone until he meets a mysterious girl that goes by the name Kuro. The two of them will try their hardest to help each other survive, especially after they learn a little more about what's going on by 4 high school girls.