Nineteen years ago, a pandemic crossed the earth that killed every single cat in the world. Not one survived - but all of them bit someone before they died. The reason why was a mystery for about a year. It was at this time that the first bitten human had a child. But that child was only half human. The other half was feline.
This phenomenon was occuring all over the planet, with more half cat kids every day as the bitten people started families.
It has been decided that these "kats", with half the DNA, have only half the human reasoning as a normal human. Thus, to the world, they are no more than half-breed pets. They have no place in the world except to wear a collar at a full human's side.
A small number of kats escaped, survived, and rebel against the new laws of man. But how could they possibly make it alive when the world is out to get them?