Life is normal. Animals are animals, humans are humans. Suddenly, that changes. One day, all of the animals on the planet turn into humans and vice versa. Everybody is confused, but eventually the animals figure out they can kill humans who turned into animals and build societies to take revenge on humans and turn them into livestock. Humans, on the other hand, have to band together with other human-animals in order to figure out a way to revert the change in order to retain a more capable form. However, some humans enjoy being animals, and even want to stay as animals permanently. As a result, the humans are divided and face a greater threat of humanoid animals with all of the technology they previously possessed.
Probably call it Inverse or something.