The apocalypse happened. The FZ virus swept over and infecting most of humanity. FZ has many parallels to a zombie virus but instead of biting to transfer the virus, it is done through cum and pussy juices. Once infected with the virus, the infected person will usually transform into a futanari and only able to think about sex to transform the next uninfected person! There are many different types of infected to watch out for with their own unique behaviours and general looks.