Overrun

I think Overrun is a better title than The Evil Rats xD
This story is about a man called Ben Jones, he is an exterminator of rouge pest's, can be rats, or something like that, he is called in to investigative a death which happened the night before, not knowing what it's about he goes along, more and more attacks start happening all over the place once it is revealed to him what killed them. Can he dive back into his dark past he is so eager to forget? Can he survive being overrun?